Prof. Hadis Morkoç Profile

Prof. Hadis Morkoç

Founders Professor at Virginia Commonwealth Univ

SPIE Involvement:

Conference Chair | Editor | Author

Publications (138)

Proceedings Article | 16 March 2023 Presentation

Investigation of plasmonic losses in TCOs based on heavily doped ZnO (Conference Presentation)

Vitaliy Avrutin, Dhruv Fomra, Nathaniel Kinsey, Natalia Izyumskaya, Ümit Özgür, Hadis Morkoç, Martin Feneberg, Ruediger Goldhahn

Proceedings Volume PC12422, PC1242211 (2023) https://doi.org/10.1117/12.2661314

KEYWORDS: Plasmonics, Zinc oxide, Atomic layer deposition, Transparent conductors, Thin films, Spectroscopic ellipsometry, Infrared spectroscopy, X-ray diffraction, Transparent conducting oxide, Thin film deposition

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Proceedings Article | 16 March 2023 Presentation

High-field electron transport and microwave noise in ZnO channels with 2 dimensional electron gas (Conference Presentation)

Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç, Linas Ardaravičius, Arthur Šimukovič, Emilis Šermukšnis

Proceedings Volume PC12422, PC124220K (2023) https://doi.org/10.1117/12.2661416

KEYWORDS: Electron transport, Microwave radiation, Zinc oxide, Resistance, Temperature metrology, Phonons, Molecular beam epitaxy, Heterojunctions

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Proceedings Article | 16 March 2023 Presentation + Paper

Demonstration of thick phase-pure β-Ga2O3 on a c-plane sapphire substrate using MOCVD

Mohi Uddin Jewel, Samiul Hasan, Scott Crittenden, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç, Iftikhar Ahmad

Proceedings Volume 12422, 1242204 (2023) https://doi.org/10.1117/12.2661097

KEYWORDS: Gallium, Annealing, Sapphire, Metalorganic chemical vapor deposition, Silicon, Thin films, Surface roughness, Semiconductors, Gallium oxide, Reflection

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Proceedings Article | 15 March 2023 Presentation + Paper

Gate leakage current and threshold voltage characteristics of β-Ga2O3 passivated AlGaN/GaN based heterojunction field effect transistor

Samiul Hasan, Mohi Uddin Jewel, Scott Crittenden, Dongkyu Lee, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç, Iftikhar Ahmad

Proceedings Volume 12421, 124210A (2023) https://doi.org/10.1117/12.2668236

KEYWORDS: Dielectrics, Gallium nitride, Heterojunctions, Field effect transistors, Oxides, Passivation, Gallium, Metalorganic chemical vapor deposition, Interfaces, Capacitance

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Proceedings Article | 5 March 2021 Presentation

Welcome and Introduction to SPIE Conference 11686

Hiroshi Fujioka, Hadis Morkoç, Ulrich Schwarz

Proceedings Volume 11686, 1168602 (2021) https://doi.org/10.1117/12.2592144

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Proceedings Article | 5 March 2021 Presentation

DC and microwave performance of BeMgZnO/ZnO heterostructure field effect transistors

Kai Ding, Vitaliy Avrutin, Natalia Izyumskaya, Ümit Özgür, Hadis Morkoç, Emilis Šermukšnis, Arvydas Matulionis

Proceedings Volume 11687, 116871D (2021) https://doi.org/10.1117/12.2586813

KEYWORDS: Heterojunctions, Field effect transistors, Microwave radiation, Zinc oxide, Sapphire, Plasmons, Fourier transforms, Dielectrics

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Proceedings Article | 10 March 2020 Presentation

Low-temperature growth of Al-doped ZnO by atomic layer deposition for plasmonics (Conference Presentation)

Dhruv Fomra, Kai Ding, Vitaliy Avrutin, Natalia Izyumskaya, Nathaniel Kinsey, Ümit Özgür, Hadis Morkoç

Proceedings Volume 11281, 1128119 (2020) https://doi.org/10.1117/12.2550537

KEYWORDS: Atomic layer deposition, Plasmonics, Zinc oxide, Aluminum, Telecommunications, Transparent conducting oxide, Sapphire, Molecular beam epitaxy, Crystals, Gallium

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Proceedings Article | 5 March 2020 Presentation + Paper

Molecular beam epitaxy of Zn-polar ZnO/BeMgZnO heterostructure field effect transistors on GaN and c-sapphire: a comparative study

Kai Ding, Vitaliy Avrutin, Natalia Izyumskaya, Ümit Özgür, Hadis Morkoç

Proceedings Volume 11281, 112811Q (2020) https://doi.org/10.1117/12.2550534

KEYWORDS: Zinc oxide, Gallium nitride, Sapphire, Heterojunctions, Molecular beam epitaxy, Field effect transistors, Metalorganic chemical vapor deposition, Electronics, Semiconductors, Polarization

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Proceedings Article | 16 February 2020 Paper

PECVD grown SiN photonic crystal micro-domes for the light extraction enhancement of GaN LEDs

M. Genç, V. Sheremet, İ. Altuntaş, İ. Demir, E. Gür, S. Elagöz, O. Gülseren, Ü. Özgür, V. Avrutin, H. Morkoç, A. Aydınlı

Proceedings Volume 11280, 112800O (2020) https://doi.org/10.1117/12.2547206

KEYWORDS: Light emitting diodes, Silver, Photonic crystals, Gallium nitride, Sapphire, Plasma enhanced chemical vapor deposition, Silicon, Refractive index, Reflection, Light scattering

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Proceedings Article | 1 March 2019 Presentation + Paper

Electrical properties of BeMgZnO/ZnO heterostructures with high-density two-dimensional electron gas

K. Ding, V. Avrutin, N. Izyumskaya, Ü. Özgür, H. Morkoç, E. Šermukšnis, A. Matulionis

Proceedings Volume 10919, 1091917 (2019) https://doi.org/10.1117/12.2511644

KEYWORDS: Heterojunctions, Magnesium, Beryllium, Zinc oxide, Phonons, Zinc, Profiling, Interfaces, Gallium nitride, Oxygen

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Proceedings Article | 23 February 2018 Presentation + Paper

Recent progress in nonpolar and semi-polar GaN light emitters on patterned Si substrates

K. Ding, V. Avrutin, N. Izyumskaya, S. Metzner, F. Bertram, J. Christen, U. Ozgur, H. Morkoc

Proceedings Volume 10532, 1053208 (2018) https://doi.org/10.1117/12.2291281

KEYWORDS: Gallium nitride, Silicon, Light emitting diodes, Indium gallium nitride, Crystals, Scanning electron microscopy, Indium, Polarization, Optical properties, Interfaces

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Proceedings Article | 24 February 2017 Paper

Quaternary BeMgZnO by plasma-enhanced molecular beam epitaxy for BeMgZnO/ZnO heterostructure devices

M. B. Ullah, M. Toporkov, V. Avrutin, Ü. Özgür, D. Smith, H. Morkoç

Proceedings Volume 10105, 101050J (2017) https://doi.org/10.1117/12.2260814

KEYWORDS: Heterojunctions, Molecular beam epitaxy, Zinc oxide, Field effect transistors, Magnesium, Beryllium, Zinc, Polarization, Crystals, Gallium nitride, Transmission electron microscopy

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We investigated the crystal structure, growth kinetics and electrical properties of BeMgZnO/ZnO heterostructures grown by Molecular Beam Epitaxy (MBE). Transmission Electron Microscopy (TEM) studies revealed that incorporation of Mg into the BeZnO solid solution eliminates the high angle grain boundaries that are the major structural defects in ternary BeZnO. The significant improvement of x-ray diffraction intensity from quaternary BeMgZnO alloy compared to ternary BeZnO was attributed to the reduction of lattice strain, which is present in the latter due to the large difference of covalent radii between Be and Zn (1.22 Å for Zn, 0.96 Å for Be). Incorporation of Mg, which has a larger covalent radius of 1.41Å, reduced the strain in BeMgZnO thin films and also enhanced Be incorporation on lattice sites in the wurtzite lattice. The Zn/(Be + Mg) ratio necessary to obtain single-crystal O-polar BeMgZnO on (0001) GaN/sapphire templates was found to increase with increasing substrate temperature:3.9, 6.2, and 8.3 at substrate temperatures of 450°C, 475°C, and 500°C, respectively. Based on analysis of photoluminescence spectra from Be_0.03Mg_yZn_0.97-yO and evolution of reflection high-energy electron diffraction patterns observed in situ during the MBE growth, it has been deduced that more negative formation enthalpy of MgO compared to ZnO and the increased surface mobility of Mg adatoms at elevated substrate temperatures give rise to the nucleation of a MgO-rich wurtzite phase at relatively low Zn/(Be + Mg) ratios. We have demonstrated both theoretically and experimentally that the incorporation of Be into the barrier in Zn-polar BeMgZnO/ZnO and O-polar ZnO/BeMgZnO polarization doped heterostructures allows the alignment of piezoelectric polarization vector with that of spontaneous polarization due to the change of strain sign, thus increasing the amount of net polarization. This made it possible to achieve Zn-polar BeMgZnO/ZnO heterostructures grown on GaN/sapphire templates with two-dimensional electron gas densities substantially exceeding those in Zn-polar MgZnO/ZnO and O-polar ZnO/MgZnO heterostructures with similar Mg content.

Proceedings Article | 27 February 2016 Paper

Exciton localization and large Stokes shift in quaternary BeMgZnO grown by molecular beam epitaxy

Mykyta Toporkov, Md. Barkat Ullah, Shopan Hafiz, Tanner Nakagawara, Vitaliy Avrutin, Hadis Morkoç, Ümit Özgür

Proceedings Volume 9749, 974910 (2016) https://doi.org/10.1117/12.2214156

KEYWORDS: Excitons, Thin films, Molecular beam epitaxy, Luminescence, Optoelectronic devices, Carrier dynamics, Zinc oxide, Solids, Ultraviolet radiation, Optoelectronics, Magnesium, Beryllium, Gallium nitride, Absorption, Zinc, Sapphire

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Owing to wide range bandgap tunability to more than 5 eV, the quaternary (Be,Mg)ZnO solid solutions are attractive for a variety of UV optoelectronic applications, inclusive of solar blind photodetectors, and intersubband transition devices. The mutual compensation effects of Be and Mg on the formation energy and strain allows a wide range of compositions and bandgaps beyond those achievable by MgZnO and BeZnO ternaries. Localization effects are well pronounced in such wide-bandgap semiconductor alloys due to large differences in metal covalent radii and the lattice constants of the binaries, resulting in strain-driven compositional variations within the film and consequently large potential fluctuations, in addition to that possibly caused by defects. However, carrier localization may suppress recombination through nonradiative channels, and thus, facilitate high-efficiency optoelectronic devices. To investigate potential fluctuations and localization in Be_xMg_yZn(_1-x-y)O films grown by plasma-assisted molecular beam epitaxy, optical absorption and steady-state and time-resolved photoluminescence (PL) measurements were performed. O-polar Be_xMg_yZn(_1-x-y)O samples grown on GaN templates with compositions up to x = 0.04 and y = 0.18 were used for timeresolved studies, and O-polar Be_xMg_yZn(_1-x-y)O samples grown on sapphire with compositions up to x = 0.19 and y = 0.52 were used for absorption measurements. From spectrally resolved PL transients, BeMgZnO samples with higher Mg/Be content ratio were found to exhibit smaller localization depth, Δ₀=98 meV for Be_0.04Mg_0.17Zn_0.79O and Δ₀=173 meV for Be_0.10Mg_0.25Zn_0.65O, compared to samples with smaller Mg/Be ratio, Δ₀=268 meV for Be_0.11Mg_0.15Zn_0.74O. Similar correlation is observed in temporal redshift of the PL peak position of 8 meV, 42 meV and 55 meV for Be_0.04Mg_0.17Zn_0.79O, Be_0.10Mg_0.25Zn_0.65O and Be_0.11Mg_0.15Zn_0.74O, respectively, that originates from potential fluctuations and removal of band filling effect in the localized states. PL transients indicate that emission at low temperature is dominated by recombination of localized excitons, which exhibit decay times as long as τ = 0.36 ns at the peak position. The Sshaped behavior of PL peak with change in temperature was observed for the quaternary alloy Be_0.04Mg_0.17Zn_0.79O. The degree of localization σ was determined to be 22 meV. Relatively high potential fluctuations and localization energy lead to a strong Stokes shift, which increased with bandgap reaching ~0.5 eV for O-polar BeMgZnO on sapphire with 4.6 eV absorption edge.

Proceedings Article | 26 February 2016 Paper

Enhancement of indium incorporation to InGaN MQWs on AlN/GaN periodic multilayers

Morteza Monavarian, Shopan Hafiz, Saikat Das, Natalia Izyumskaya, Ümit Özgür, Hadis Morkoç, Vitaliy Avrutin

Proceedings Volume 9748, 974825 (2016) https://doi.org/10.1117/12.2213777

KEYWORDS: Indium gallium nitride, Indium, Gallium nitride, Luminescence, Heterojunctions, Quantum wells, X-ray diffraction, Aluminum nitride, Nanostructures, Quantum efficiency, Indium nitride, Satellites, Gallium

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Proceedings Article | 26 February 2016 Paper

Exciton localization in (11-22)-oriented semi-polar InGaN multiple quantum wells

Morteza Monavarian, Daniel Rosales, Bernard Gil, Natalia Izyumskaya, Saikat Das, Ümit Özgür, Hadis Morkoç, Vitaliy Avrutin

Proceedings Volume 9748, 974826 (2016) https://doi.org/10.1117/12.2213835

KEYWORDS: Excitons, Indium gallium nitride, Quantum wells, Luminescence, Quantum efficiency, Gallium nitride, Heterojunctions, Epitaxial lateral overgrowth, Temperature metrology, Picosecond phenomena, Indium, Lab on a chip, Light emitting diodes, Gallium

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Proceedings Article | 26 February 2016 Paper

Optical investigation of microscopic defect distribution in semi-polar (1-101 and 11-22) InGaN light-emitting diodes

Shopan Hafiz, Nicolas Andrade, Morteza Monavarian, Natalia Izyumskaya, Saikat Das, Fan Zhang, Vitaliy Avrutin, Hadis Morkoç, Ümit Özgür

Proceedings Volume 9748, 974828 (2016) https://doi.org/10.1117/12.2213908

KEYWORDS: Light emitting diodes, Near field optics, Near field scanning optical microscopy, Indium gallium nitride, Luminescence, Epitaxial lateral overgrowth, Nanostructures, Gallium nitride, Indium, Scanning electron microscopy, Quantum efficiency

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Proceedings Article | 26 February 2016 Paper

Wurtzite/zinc-blende electronic-band alignment in basal-plane stacking faults in semi-polar GaN

Morteza Monavarian, Shopan Hafiz, Natalia Izyumskaya, Saikat Das, Ümit Özgür, Hadis Morkoç, Vitaliy Avrutin

Proceedings Volume 9748, 974827 (2016) https://doi.org/10.1117/12.2213859

KEYWORDS: Gallium nitride, Interfaces, Ultrafast phenomena, Polarization, Optical spectroscopy, Spectroscopy, Femtosecond phenomena, Electrons, Quantum wells, Picosecond phenomena, Scanning transmission electron microscopy, Laser beam diagnostics, Sapphire, Excitons

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Proceedings Article | 13 March 2015 Paper

Indium-incorporation efficiency in semipolar (11-22) oriented InGaN-based light emitting diodes

Morteza Monavarian, Sebastian Metzner, Natalia Izyumskaya, Serdal Okur, Fan Zhang, Nuri Can, Saikat Das, Vitaliy Avrutin, Ümit Özgür, Frank Bertram, Jürgen Christen, Hadis Morkoç

Proceedings Volume 9363, 93632P (2015) https://doi.org/10.1117/12.2080325

KEYWORDS: Indium, Gallium nitride, Light emitting diodes, Indium gallium nitride, Heterojunctions, Epitaxial lateral overgrowth, Metalorganic chemical vapor deposition, Quantum efficiency, Indium nitride, Chemical vapor deposition

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Proceedings Article | 13 March 2015 Paper

Active region dimensionality and quantum efficiencies of InGaN LEDs from temperature dependent photoluminescence transients

Nuri Can, Serdal Okur, Morteza Monavarian, Fan Zhang, Vitaliy Avrutin, Hadis Morkoç, Ali Teke, Ümit Özgür

Proceedings Volume 9363, 93632U (2015) https://doi.org/10.1117/12.2179637

KEYWORDS: Light emitting diodes, Quantum efficiency, Indium gallium nitride, Luminescence, Excitons, Quantum wells, Polarization, Internal quantum efficiency, External quantum efficiency, Temperature metrology

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Proceedings Article | 13 March 2015 Paper

Temperature-dependent time-resolved photoluminescence measurements of (1-101)-oriented semi-polar AlGaN/GaN MQWs

Daniel Rosales, Bernard Gil, Morteza Monavarian, Fan Zhang, Serdal Okur, Natalia Izyumskaya, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç

Proceedings Volume 9363, 93630J (2015) https://doi.org/10.1117/12.2076207

KEYWORDS: Lab on a chip, Luminescence, Excitons, Gallium nitride, Quantum wells, Polarization, Silicon, Picosecond phenomena, Oscillators, Anisotropy

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Proceedings Article | 13 March 2015 Paper

Enhancement of optical and structural quality of semipolar (11-22) GaN by introducing nanoporous SiNx interlayers

Morteza Monavarian, Sebastian Metzner, Natalia Izyumskaya, Marcus Müller, Serdal Okur, Fan Zhang, Nuri Can, Saikat Das, Vitaliy Avrutin, Ümit Özgür, Frank Bertram, Juergen Christen, Hadis Morkoç

Proceedings Volume 9363, 93632I (2015) https://doi.org/10.1117/12.2079180

KEYWORDS: Gallium nitride, Epitaxial lateral overgrowth, X-ray optics, Scanning electron microscopy, Luminescence, X-ray diffraction, X-rays, Excitons, Sapphire, Chemical vapor deposition

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Proceedings Article | 13 March 2015 Paper

Enhancement of coherent acoustic phonons in InGaN multiple quantum wells

Shopan Hafiz, Fan Zhang, Morteza Monavarian, Vitaliy Avrutin, Hadis Morkoç, Ümit Özgür

Proceedings Volume 9363, 93632J (2015) https://doi.org/10.1117/12.2079245

KEYWORDS: Phonons, Acoustics, Quantum wells, Indium gallium nitride, Terahertz radiation, Mirrors, Gallium nitride, Superlattices, Indium, Laser beam diagnostics

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Proceedings Article | 13 March 2015 Paper

Strong carrier localization in stacking faults in semipolar (11-22) GaN

Serdal Okur, Morteza Monavarian, Saikat Das, Natalia Izyumskaya, Fan Zhang, Vitaliy Avrutin, Hadis Morkoç, Ümit Özgür

Proceedings Volume 9363, 93632N (2015) https://doi.org/10.1117/12.2080248

KEYWORDS: Gallium nitride, Excitons, Polarization, Point spread functions, Luminescence, Crystals, Temperature metrology, Applied physics, Quantum wells, Aluminum nitride

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Proceedings Article | 13 March 2015 Paper

Strong exciton-photon coupling in hybrid InGaN-based microcavities on GaN substrates

Serdal Okur, Alexander Franke, Fan Zhang, Vitaliy Avrutin, Hadis Morkoç, Frank Bertram, Juergen Christen, Ümit Özgür

Proceedings Volume 9363, 93632O (2015) https://doi.org/10.1117/12.2080265

KEYWORDS: Gallium nitride, Polaritons, Optical microcavities, Reflectivity, Excitons, Photons, Indium gallium nitride, Quantum wells, Luminescence, Temperature metrology

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Proceedings Article | 8 March 2014 Paper

Determination of carrier diffusion length in p- and n-type GaN

Shopan Hafiz, Sebastian Metzner, Fan Zhang, Morteza Monavarian, Vitaliy Avrutin, Hadis Morkoç, Christopher Karbaum, Frank Bertram, Jürgen Christen, Bernard Gil, Ümit Özgür

Proceedings Volume 8986, 89862C (2014) https://doi.org/10.1117/12.2040645

KEYWORDS: Diffusion, Gallium nitride, Indium gallium nitride, Magnesium, Absorption, Luminescence, Line scan image sensors, Doping, Integration, Sapphire

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Proceedings Article | 8 March 2014 Paper

Impact of extended defects on optical properties of (1-101)GaN grown on patterned Si

S. Okur, N. Izyumskaya, F. Zhang, V. Avrutin, S. Metzner, C. Karbaum, F. Bertram, J. Christen, H. Morkoç, Ü. Özgür

Proceedings Volume 8986, 89862B (2014) https://doi.org/10.1117/12.2040621

KEYWORDS: Gallium nitride, Near field optics, Light emitting diodes, Polarization, Silicon, Point spread functions, Near field scanning optical microscopy, Indium gallium nitride, Luminescence, Excitons

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Proceedings Article | 8 March 2014 Paper

Optical properties of m-plane GaN grown on patterned Si(112) substrates by MOCVD using a two-step approach

N. Izyumskaya, S. Okur, F. Zhang, M. Monavarian, V. Avrutin, Ü. Özgür, S. Metzner, C. Karbaum, F. Bertram, J. Christen, H. Morkoç

Proceedings Volume 8986, 898628 (2014) https://doi.org/10.1117/12.2037930

KEYWORDS: Gallium nitride, Near field optics, Metalorganic chemical vapor deposition, Silicon, Near field scanning optical microscopy, Scanning electron microscopy, Point spread functions, Image quality, Excitons, Chemical vapor deposition

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Proceedings Article | 8 March 2014 Paper

Effect of electron density on cutoff frequency of III-N HFETs

Arvydas Matulionis, Hadis Morkoç

Proceedings Volume 8986, 89861D (2014) https://doi.org/10.1117/12.2036914

KEYWORDS: Phonons, Gallium nitride, Ultrafast phenomena, Heterojunctions, Scattering, Acoustics, Transistors, Plasmons, Capacitance, Reliability

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Proceedings Article | 8 March 2014 Paper

Polarized time-resolved photoluminescence measurements of m-plane AlGaN/GaN MQWs

Daniel Rosales, B. Gil, T. Bretagnon, F. Zhang, S. Okur, M. Monavarian, N. Izioumskaia, V. Avrutin, Ü. Özgür, H. Morkoç, J. Leach

Proceedings Volume 8986, 89860L (2014) https://doi.org/10.1117/12.2036984

KEYWORDS: Luminescence, Quantum wells, Polarization, Gallium nitride, Temperature metrology, Excitons, Anisotropy, Picosecond phenomena, 3D modeling, Tantalum

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Proceedings Article | 27 February 2014 Paper

Estimation of carrier leakage in InGaN light emitting diodes from photocurrent measurements

Shopan Hafiz, Fan Zhang, Morteza Monavarian, Serdal Okur, Vitaliy Avrutin, Hadis Morkoç, Ümit Özgür

Proceedings Volume 9003, 90031R (2014) https://doi.org/10.1117/12.2040926

KEYWORDS: Light emitting diodes, Indium gallium nitride, Electron transport, Band structure simulations, Heterojunctions, Continuous wave operation, Helium cadmium lasers, Metalorganic chemical vapor deposition, Plasma etching, Electrodes

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Proceedings Article | 27 March 2013 Paper

Microwave performance of AlGaN/AlN/GaN-based single and coupled channels HFETs

R. Ferreyra, X. Li, F. Zhang, C. Zhu, N. Izyumskaya, C. Kayis, V. Avrutin, Ü. Özgür, H. Morkoç

Proceedings Volume 8625, 86252B (2013) https://doi.org/10.1117/12.2005165

KEYWORDS: Phonons, Gallium nitride, Microwave radiation, Heterojunctions, Plasmons, Transistors, Aluminum, Aluminum nitride, Lithium, Reliability

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Proceedings Article | 4 March 2013 Paper

Depth distribution of carrier lifetimes in semipolar (1101) GaN grown by MOCVD on patterned Si substrates

N. Izyumskaya, S. Okur, F. Zhang, V. Avrutin, Ü. Özgür, S. Metzner, C. Karbaum, F. Bertram, J. Christen, H. Morkoç

Proceedings Volume 8625, 86252G (2013) https://doi.org/10.1117/12.2005514

KEYWORDS: Gallium nitride, Near field scanning optical microscopy, Silicon, Metalorganic chemical vapor deposition, Optical properties, Near field optics, Luminescence, Light emitting diodes, Carrier dynamics, Temperature metrology

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Proceedings Article | 4 March 2013 Paper

InGaN based multi-double heterostructure light-emitting diodes with electron injector layers

F. Zhang, S. Hafiz, X. Li, S. Okur, V. Avrutin, Ü. Özgür, H. Morkoç

Proceedings Volume 8625, 86251J (2013) https://doi.org/10.1117/12.2003162

KEYWORDS: Light emitting diodes, Electroluminescence, Indium gallium nitride, Quantum efficiency, External quantum efficiency, Heterojunctions, Internal quantum efficiency, Temperature metrology, Quantum wells, Luminescence

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Proceedings Article | 4 March 2013 Paper

GaN-based vertical cavity lasers with semiconductor/dielectric and all dielectric reflectors

F. Zhang, S. Okur, S. Hafiz, V. Avrutin, Ü. Özgür, H. Morkoç

Proceedings Volume 8625, 86252F (2013) https://doi.org/10.1117/12.2005442

KEYWORDS: Dielectrics, Gallium nitride, Epitaxial lateral overgrowth, Reflectivity, Semiconductor lasers, Etching, Reflectors, Quantum wells, Indium gallium nitride, Modulation

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Proceedings Article | 4 March 2013 Paper

Recombination dynamics in non-polar m-plane GaN investigated by time- and polarization-resolved photoluminescence

Serdal Okur, Kestutis Jarašiūnas, Shopan din Ahmad Hafiz, Jacob Leach, Tania Paskova, Vitaliy Avrutin, Hadis Morkoç, Ümit Özgür

Proceedings Volume 8625, 86252D (2013) https://doi.org/10.1117/12.2005252

KEYWORDS: Excitons, Polarization, Gallium nitride, Luminescence, Temperature metrology, Spectroscopy, Dual energy x-ray absorptiometry, Polarizers, Continuous wave operation, Time resolved spectroscopy

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Proceedings Article | 4 March 2013 Paper

Investigation of microwave and noise properties of InAlN/GaN HFETs after electrical stress: role of surface effects

Congyong Zhu, Fan Zhang, Romualdo Ferreyra, Xing Li, Cemil Kayis, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç

Proceedings Volume 8625, 86252H (2013) https://doi.org/10.1117/12.2000558

KEYWORDS: Capacitance, Microwave radiation, Fourier transforms, Gallium nitride, Phase measurement, Phonons, Heterojunctions, Field effect transistors, Interfaces, Reliability

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Proceedings Article | 28 February 2012 Paper

Recombination and diffusion processes in polar and nonpolar bulk GaN investigated by time-resolved photoluminescence and nonlinear optical techniques

Kęstutis Jarašiūnas, Patrik Ščajev, Saulius Nargelas, Ramūnas Aleksiejūnas, Jacob Leach, Tania Paskova, Serdal Okur, Ümit Özgür, Hadis Morkoç

Proceedings Volume 8262, 82620G (2012) https://doi.org/10.1117/12.906303

KEYWORDS: Diffusion, Gallium nitride, Carrier dynamics, Luminescence, Excitons, Picosecond phenomena, Interfaces, Crystals, Transient nonlinear optics, Absorption

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Proceedings Article | 28 February 2012 Paper

Effect of MOCVD growth conditions on the optical properties of semipolar (1-101) GaN on Si patterned substrates

N. Izyumskaya, S. Liu, V. Avrutin, S. Okur, F. Zhang, Ü. Özgür, S. Metzner, C. Karbaum, F. Bertram, J. Christen, D. Smith, H. Morkoç

Proceedings Volume 8262, 826224 (2012) https://doi.org/10.1117/12.909235

KEYWORDS: Gallium nitride, Silicon, Sapphire, Metalorganic chemical vapor deposition, Optical properties, Scanning electron microscopy, Quantum wells, Light emitting diodes, Luminescence, Chemical vapor deposition

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Proceedings Article | 28 February 2012 Paper

Degradation mechanism of InAlN/GaN based HFETs under high electric field stress

Congyong Zhu, Mo Wu, Cemil Kayis, Fan Zhang, Xing Li, Romualdo Ferreyra, Vitaliy Avrutin, Ümit Özgur, Hadis Morkoç

Proceedings Volume 8262, 826225 (2012) https://doi.org/10.1117/12.903983

KEYWORDS: Field effect transistors, Piezoelectric effects, Gallium nitride, Transistors, Applied physics, Reliability, Phonons, Heterojunctions, Lithium, Molybdenum

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Proceedings Article | 28 February 2012 Paper

Impact of carrier localization, recombination, and diffusivity on excited state dynamics in InGaN/GaN quantum wells

T. Malinauskas, A. Kadys, T. Grinys, S. Nargelas, R. Aleksiejūnas, S. Miasojedovas, J. Mickevičius, R. Tomašiūnas, K. Jarašiūnas, M. Vengris, S. Okur, V. Avrutin, X. Li, F. Zhang, Ü. Özgür, H. Morkoç

Proceedings Volume 8262, 82621S (2012) https://doi.org/10.1117/12.906488

KEYWORDS: Quantum wells, Indium gallium nitride, Indium, Picosecond phenomena, Light emitting diodes, Diffusion, Gallium nitride, Carrier dynamics, Absorbance, Diffraction

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Proceedings Article | 28 February 2012 Paper

Measurements of off-state electrical stress in InAlN/AlN/GaN heterostructure field-effect transistors with varying In compositions

Romualdo Ferreyra, Cemil Kayis, Congvong Zhu, Ümit Özgür, Hadis Morkoç

Proceedings Volume 8262, 82621U (2012) https://doi.org/10.1117/12.907515

KEYWORDS: Transistors, Heterojunctions, Gallium nitride, Phase measurement, Reliability, Indium, Measurement devices, Calibration, Semiconducting wafers, Piezoelectric effects

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Proceedings Article | 28 February 2012 Paper

Electrical properties of ZnO:Ga as a transparent conducting oxide in InGaN based light emitting diodes

H. Y. Liu, X. Li, F. Zhang, V. Avrutin, N. Izyumskaya, Ü. Özgür, A. B. Yankovich, A. V. Kvit, P. M. Voyles, H. Morkoç

Proceedings Volume 8262, 826226 (2012) https://doi.org/10.1117/12.903930

KEYWORDS: Zinc oxide, Scattering, Gallium nitride, Light emitting diodes, Sapphire, Annealing, Crystals, Indium gallium nitride, Gallium, Phonons

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Proceedings Article | 28 February 2012 Paper

Degradation analysis of InAlN/AlN/GaN heterostructure field-effect transistors using low-frequency noise and current-transient methods: hot-phonon effects

Cemil Kayis, R. Ferreyra, Congyong Zhu, Mo Wu, X. Li, Ü. Özgür, A. Matulionis, H. Morkoç

Proceedings Volume 8262, 82621W (2012) https://doi.org/10.1117/12.908501

KEYWORDS: Phonons, Gallium nitride, Heterojunctions, Transistors, Semiconducting wafers, Phase measurement, Ultrafast phenomena, Astatine, Molybdenum, Ultrafast measurement systems

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Proceedings Article | 28 February 2012 Paper

Temperature dependent behavior of the SPV for n-type GaN

J. McNamara, M. Foussekis, H. Liu, H. Morkoç, M. Reshchikov, A. Baski

Proceedings Volume 8262, 826213 (2012) https://doi.org/10.1117/12.910289

KEYWORDS: Gallium nitride, Temperature metrology, Oxygen, Electrons, Ultraviolet radiation, Adsorption, Statistical modeling, Data modeling, Interfaces, Vapor phase epitaxy

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Proceedings Article | 23 February 2012 Paper

Pyramid nano-voids in GaN and InGaN

A. Yankovich, A. Kvit, H. Liu, X. Li, F. Zhang, V. Avrutin, N. Izyumskaya, Ü. Özgür, H. Morkoc, P. Voyles

Proceedings Volume 8262, 826205 (2012) https://doi.org/10.1117/12.912097

KEYWORDS: Gallium nitride, Scanning transmission electron microscopy, Indium gallium nitride, Gallium, Transmission electron microscopy, Quantum wells, Carbon, Metalorganic chemical vapor deposition, Imaging spectroscopy, Sensors

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Proceedings Article | 10 February 2012 Paper

The impact of active layer design on quantum efficiency of InGaN light emitting diodes

F. Zhang, X. Li, S. Okur, V. Avrutin, Ü. Özgür, H. Morkoç, S. Hong, S. Yen, T. Hsu, A. Matulionis

Proceedings Volume 8262, 82621G (2012) https://doi.org/10.1117/12.903931

KEYWORDS: Light emitting diodes, External quantum efficiency, Indium gallium nitride, Quantum efficiency, Quantum wells, Lithium, Gallium, Electroluminescence, Gallium nitride, Nickel

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Proceedings Article | 11 March 2011 Paper

Two-dimensional drift-diffusion simulation of GaN HFETs

Qian Fan, Hadis Morkoç

Proceedings Volume 7939, 79391O (2011) https://doi.org/10.1117/12.877336

KEYWORDS: Gallium nitride, Polarization, Field effect transistors, Semiconductors, Heterojunctions, Transistors, Electron transport, Device simulation, Light emitting diodes, Indium nitride

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Proceedings Article | 10 March 2011 Paper

1/f Noise in Schottky diodes

Peter Handel, Hadis Morkoç

Proceedings Volume 7939, 79391S (2011) https://doi.org/10.1117/12.876254

KEYWORDS: Diodes, Terahertz radiation, Sensors, Semiconductors, Scattering, Diffusion, Gallium nitride, Quantum physics, Photons, Phonons

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Proceedings Article | 4 March 2011 Paper

Deep inductively coupled plasma etching of ELO-GaN grown with high fill factor

Haiyong Gao, Jaesoong Lee, Xianfeng Ni, Jacob Leach, Ümit Özgür, Hadis Morkoç

Proceedings Volume 7939, 793920 (2011) https://doi.org/10.1117/12.876870

KEYWORDS: Etching, Gallium nitride, Scanning electron microscopy, Epitaxial lateral overgrowth, Dielectrics, Plasma etching, Silica, Metalorganic chemical vapor deposition, Atomic force microscopy, Nickel

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Proceedings Article | 4 March 2011 Paper

New factors affecting HFET stability, 1/f noise, and reliability

Peter Handel, Hadis Morkoç

Proceedings Volume 7939, 79390H (2011) https://doi.org/10.1117/12.876251

KEYWORDS: Phonons, Polarization, Reliability, Plasmons, Field effect transistors, Gallium nitride, Electrons, Picosecond phenomena, Channel projecting optics, Resistance

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Proceedings Article | 4 March 2011 Paper

Effect of substrate offcut on AlGaN/GaN HFET structures on bulk GaN substrates

J. Leach, N. Biswas, T. Paskova, E. Preble, K. Evans, M. Wu, X. Ni, X. Li, Ü. Özgür, H. Morkoç

Proceedings Volume 7939, 79390E (2011) https://doi.org/10.1117/12.875755

KEYWORDS: Gallium nitride, Heterojunctions, Aluminum, Resistance, Semiconducting wafers, Sapphire, Crystals, Polishing, Epitaxy, X-ray diffraction

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Proceedings Article | 4 March 2011 Paper

Heterostructure designs for enhanced performance and reliability in GaN HFETs: camelback channels

J. Leach, M. Wu, H. Morkoç, M. Ramonas, A. Matulionis

Proceedings Volume 7939, 79391P (2011) https://doi.org/10.1117/12.877717

KEYWORDS: Phonons, Electrons, Gallium nitride, Heterojunctions, Plasmons, Reliability, Scattering, Picosecond phenomena, Field effect transistors, Channel projecting optics

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Proceedings Article | 4 March 2011 Paper

Vertical composition variation in nominally uniform InGaN layers revealed by aberration-corrected STEM imaging

A. Yankovich, A. Kvit, X. Li, F. Zhang, V. Avrutin, H. Liu, N. Izyumskaya, Ü. Özgür, H. Morkoç, P. Voyles

Proceedings Volume 7939, 79391E (2011) https://doi.org/10.1117/12.889392

KEYWORDS: Indium, Scanning transmission electron microscopy, Indium gallium nitride, Light emitting diodes, Gallium nitride, Transmission electron microscopy, Ions, Imaging spectroscopy, Quantum wells, Solar thermal energy

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Proceedings Article | 4 March 2011 Paper

Optimization of ZnO:Ga properties for application as a transparent conducting oxide in InGaN-based light-emitting diodes

H. Y. Liu, X. Li, S. Liu, X. Ni, V. Avrutin, N. Izyumskaya, Ü. Özgür, A. Yankovich, A. Kvit, P. Voyles, M. Reshchikov, H. Morkoç

Proceedings Volume 7939, 79392E (2011) https://doi.org/10.1117/12.875515

KEYWORDS: Light emitting diodes, Oxygen, Surface roughness, Gallium nitride, Indium gallium nitride, Transmission electron microscopy, Electrodes, 3D metrology, External quantum efficiency, Transparent conducting oxide

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Proceedings Article | 4 March 2011 Paper

Impact of ballistic electron transport on efficiency of InGaN based LEDs

F. Zhang, X. Li, S. Liu, S. Okur, V. Avrutin, Ü. Özgür, H. Morkoç, A. Matulionis, M. Kisin

Proceedings Volume 7939, 793917 (2011) https://doi.org/10.1117/12.875806

KEYWORDS: Light emitting diodes, Electron beam lithography, External quantum efficiency, Indium gallium nitride, Electron transport, Aluminum, Electroluminescence, Gallium nitride, Polarization, Phonons

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Proceedings Article | 4 March 2011 Paper

Low-frequency noise measurements of generation-recombination effect and field-assisted emission in AlGaN/GaN MOSHFETs and HFETs

Cemil Kayis, Jacob Leach, C. Y. Zhu, Mo Wu, X. Li, X. Yang, Veena Misra, Peter Handel, Ü. Özgür, H. Morkoç

Proceedings Volume 7939, 79392F (2011) https://doi.org/10.1117/12.875692

KEYWORDS: Dielectrics, Oxides, Temperature metrology, Interfaces, Gallium nitride, Scattering, Heterojunctions, Transistors, Interference (communication), Sapphire

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Proceedings Article | 4 March 2011 Paper

Low-frequency noise measurements of electrical stress in InAlN/GaN and AlGaN/GaN heterostructure field-effect transistors

Cemil Kayis, C. Y. Zhu, Mo Wu, Xing Li, Ümit Özgür, Hadis Morkoç

Proceedings Volume 7939, 79392G (2011) https://doi.org/10.1117/12.875723

KEYWORDS: Gallium nitride, Heterojunctions, Transistors, Aluminum nitride, Reliability, Phonons, Calibration, Sapphire, Field effect transistors, Neodymium

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Proceedings Article | 4 March 2011 Paper

Kelvin probe measurements of p-type GaN

M. Foussekis, X. Ni, H. Morkoç, M. Reshchikov, A. Baski

Proceedings Volume 7939, 79390A (2011) https://doi.org/10.1117/12.876166

KEYWORDS: Gallium nitride, Metalorganic chemical vapor deposition, Photons, Oxygen, Ultraviolet radiation, Statistical analysis, Adsorption, Vapor phase epitaxy, Chemical vapor deposition, Interfaces

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Proceedings Article | 3 March 2011 Paper

Photoluminescence of Mg-doped m-plane GaN grown by MOCVD on bulk GaN substrates

Bo Monemar, Plamen Paskov, Galia Pozina, Carl Hemmingsson, Peder Bergman, David Lindgren, Lars Samuelson, Xianfeng Ni, Hadis Morkoç, Tanya Paskova, Zhaoxia Bi, Jonas Ohlsson

Proceedings Volume 7939, 793907 (2011) https://doi.org/10.1117/12.874687

KEYWORDS: Gallium nitride, Magnesium, Metalorganic chemical vapor deposition, Doping, Excitons, Phonons, Luminescence, Acoustics, Quantum wells, Nanowires

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Proceedings Article | 19 February 2011 Paper

Optical properties of nonpolar (1-100) and semipolar (1-101)GaN grown by MOCVD on Si patterned substrates

N. Izyumskaya, S. J. Liu, S. Okur, M. Wu, V. Avrutin, Ü. Özgür, S. Metzner, F. Bertram, J. Christen, L. Zhou, D. Smith, H. Morkoç

Proceedings Volume 7939, 79391W (2011) https://doi.org/10.1117/12.875861

KEYWORDS: Gallium nitride, Silicon, Light emitting diodes, Sapphire, Metalorganic chemical vapor deposition, Scanning electron microscopy, Optical properties, Silica, Wet etching, Carbon

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Proceedings Article | 20 March 2010 Paper

Effect of UV exposure on the surface charge behavior for GaN

M. Foussekis, J. Ferguson, X. Ni, H. Morkoç, M. Reshchikov, A. Baski

Proceedings Volume 7602, 76020Y (2010) https://doi.org/10.1117/12.843864

KEYWORDS: Ultraviolet radiation, Oxides, Gallium nitride, Oxygen, Atomic force microscopy, Gallium, Photoemission spectroscopy, Scanning probe microscopy, Microscopy, Data acquisition

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Proceedings Article | 18 March 2010 Paper

Efficiency retention at high current injection levels in m-plane InGaN light emitting diodes

X. Li, X. Ni, J. Lee, M. Wu, Ü, Özgür, H. Morkoç, T. Paskova, G. Mulholland, K. Evans

Proceedings Volume 7602, 76021R (2010) https://doi.org/10.1117/12.843752

KEYWORDS: Light emitting diodes, External quantum efficiency, Gallium nitride, Electroluminescence, Quantum wells, Polarization, Indium gallium nitride, Sapphire, Internal quantum efficiency, Polarizers

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Proceedings Article | 17 March 2010 Paper

InGaN light-emitting diodes with highly transparent ZnO:Ga electrodes

H. Y. Liu, X. Li, X. Ni, V. Avrutin, N. Izyumskaya, Ü. Özgür, H. Morkoç

Proceedings Volume 7602, 76020I (2010) https://doi.org/10.1117/12.853327

KEYWORDS: Light emitting diodes, Electrodes, Annealing, Gallium nitride, External quantum efficiency, Indium gallium nitride, Electroluminescence, Electrons, Zinc oxide, Transparency

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Proceedings Article | 17 March 2010 Paper

Measurements of gate lag in high-quality nearly lattice matched InAlN/AlN/GaN HFET structures

J. Leach, M. Wu, X. Ni, X. Li, Ü. Özgür, H. Morkoç

Proceedings Volume 7602, 76020O (2010) https://doi.org/10.1117/12.843700

KEYWORDS: Gallium nitride, Field effect transistors, Polarization, Binary data, Sapphire, Heterojunctions, Aluminum nitride, Indium nitride, Interfaces, Solids

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Proceedings Article | 17 March 2010 Paper

Non-polar m-plane GaN on patterned Si(112) substrates by metalorganic chemical vapor deposition

X. Ni, M. Wu, J. Lee, X. Li, A. Baski, Ü. Özgür, H. Morkoç

Proceedings Volume 7602, 760220 (2010) https://doi.org/10.1117/12.845652

KEYWORDS: Gallium nitride, Silicon, Metalorganic chemical vapor deposition, Indium gallium nitride, Silica, Light emitting diodes, Internal quantum efficiency, Scanning electron microscopy, Etching, Atomic force microscopy

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Proceedings Article | 12 March 2010 Paper

Internal quantum efficiency of m-plane InGaN on Si and GaN

J. Lee, X. Ni, M. Wu, X. Li, R. Shimada, Ü. Özgür, A. Baski, H. Morkoç, T. Paskova, G. Mulholland, K. Evans

Proceedings Volume 7602, 76021N (2010) https://doi.org/10.1117/12.843727

KEYWORDS: Light emitting diodes, Indium gallium nitride, Silicon, Gallium nitride, Sapphire, Polarization, Internal quantum efficiency, Quantum wells, Optical matrix switches, Optical components

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Proceedings Article | 12 March 2010 Paper

1/f noise: a window to HFET stability

Peter Handel, Taher Sherif, Cemil Kayis, Jacob Leach, Congyong Zhu, Hadis Morkoç

Proceedings Volume 7602, 76020M (2010) https://doi.org/10.1117/12.842948

KEYWORDS: Phonons, Gallium nitride, Field effect transistors, Polarization, Plasma, Phase measurement, Reliability, Plasmons, Quantum physics, Resistance

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Proceedings Article | 11 March 2010 Paper

Plasmon-assisted dissipation of LO-mode heat in nitride 2DEG channels

Arvydas Matulionis, Juozapas Liberis, Hadis Morkoç

Proceedings Volume 7602, 76020H (2010) https://doi.org/10.1117/12.843659

KEYWORDS: Electrons, Phonons, Gallium nitride, Heterojunctions, Acoustics, Raman spectroscopy, Picosecond phenomena, Indium gallium arsenide, Solids, Microwave radiation

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Proceedings Article | 11 March 2010 Paper

On carrier spillover in c- and m-plane InGaN light-emitting diodes

J. Lee, X. Li, X. Ni, Ü. Özgür, H. Morkoç, T. Paskova, G. Mulholland, K. Evans

Proceedings Volume 7602, 760224 (2010) https://doi.org/10.1117/12.845806

KEYWORDS: Light emitting diodes, Electron beam lithography, Gallium nitride, External quantum efficiency, Polarization, Quantum wells, Indium gallium nitride, Internal quantum efficiency, Electroluminescence, Quantum efficiency

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Proceedings Article | 20 February 2009 Paper

Piezoelectric quantum 1/f noise in AlGaN HFETs and reliability

Peter Handel, Hadis Morkoç

Proceedings Volume 7216, 72160R (2009) https://doi.org/10.1117/12.812243

KEYWORDS: Phonons, Magnetism, Field effect transistors, Gallium nitride, Reliability, Acoustics, Particles, Semiconductors, Resistance, Polarization

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Proceedings Article | 20 February 2009 Paper

Transient current spectroscopy of lattice matched InAlN/AlN/GaN HFETs for identification of traps resulting in gate lag

J. Leach, Q. Fan, J. Xie, M. Wu, Ü. Özgür, H. Morkoç

Proceedings Volume 7216, 72162L (2009) https://doi.org/10.1117/12.809795

KEYWORDS: Field effect transistors, Aluminum nitride, Gallium nitride, Measurement devices, Reliability, Spectroscopes, Spectroscopy, Temperature metrology, Heterojunctions, Heart

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Proceedings Article | 20 February 2009 Paper

Electrical defects in AlGaN and InAlN

D. Johnstone, Jacob Leach, Vladimir Kovalskii, Qian Fan, Jingqiao Xie, Hadis Morkoç

Proceedings Volume 7216, 72162R (2009) https://doi.org/10.1117/12.815020

KEYWORDS: Gallium nitride, Capacitance, Temperature metrology, Spectroscopes, Aluminum, Diodes, Semiconductors, Heterojunctions, Spectroscopy, Metalorganic chemical vapor deposition

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Proceedings Article | 20 February 2009 Paper

Ferroelectric field effect transistor with a double-gate structure on AlGaN/GaN heterostructures

Bo Xiao, Jinqiao Xie, Vitaliy Avrutin, Qian Fan, Mo Wu, Hadis Morkoç

Proceedings Volume 7216, 72162M (2009) https://doi.org/10.1117/12.811671

KEYWORDS: Ferroelectric materials, Field effect transistors, Electrodes, Heterojunctions, Gallium nitride, Modulation, Semiconductors, Ferroelectric capacitors, Thin films, Switching

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Proceedings Article | 20 February 2009 Paper

Two dimensional electron gas in GaN heterojunction field effect transistors structures with AlN spacer

Qian Fan, Jacob Leach, Jinqiao Xie, Umit Ozgur, Hadis Morkoç, L. Zhou, D. Smith

Proceedings Volume 7216, 72162N (2009) https://doi.org/10.1117/12.811678

KEYWORDS: Aluminum nitride, Gallium nitride, Heterojunctions, Polarization, Field effect transistors, Data modeling, Metals, Scanning transmission electron microscopy, Nickel, Fluctuations and noise

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Proceedings Article | 19 February 2009 Paper

GaN-based vertical cavities on highly reflective and crack-free nitride distributed Bragg reflectors

X. Ni, R. Shimada, T. Kang, J. Leach, Ü. Özgür, H. Morkoç

Proceedings Volume 7216, 72162F (2009) https://doi.org/10.1117/12.807902

KEYWORDS: Reflectivity, Gallium nitride, Semiconducting wafers, Distributed Bragg reflectors, Vertical cavity surface emitting lasers, Aluminum nitride, Silica, Scanning electron microscopy, Aluminum, Photomasks

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Proceedings Article | 19 February 2009 Paper

Hot phonons in InAlN/AlN/GaN heterostructure 2DEG channels

Arvydas Matulionis, Hadis Morkoç

Proceedings Volume 7216, 721608 (2009) https://doi.org/10.1117/12.802341

KEYWORDS: Phonons, Gallium nitride, Solids, Picosecond phenomena, Temperature metrology, Monte Carlo methods, Tellurium, Heterojunctions, Microwave radiation, Scattering

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Proceedings Article | 16 February 2009 Paper

Effect of ambient on electrical and optical properties of GaN

M. Reshchikov, M. Foussekis, A. Baski, H. Morkoç

Proceedings Volume 7216, 721614 (2009) https://doi.org/10.1117/12.812258

KEYWORDS: Gallium nitride, Ultraviolet radiation, Electrons, Luminescence, Oxygen, Sapphire, Optical properties, Switching, Adsorption, Scanning probe microscopy

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Proceedings Article | 16 February 2009 Paper

Reduction of efficiency droop in InGaN-based blue LEDs

X. Ni, X. Li, J. Xie, Q. Fan, R. Shimada, Ü. Özgür, H. Morkoç

Proceedings Volume 7216, 72161W (2009) https://doi.org/10.1117/12.809877

KEYWORDS: External quantum efficiency, Light emitting diodes, Electroluminescence, Quantum efficiency, Indium gallium nitride, Quantum wells, Doping, Gallium, Blue light emitting diodes, Luminous efficiency

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Proceedings Article | 16 February 2009 Paper

Investigation of vertical current-voltage characteristics of Al(Ga)N/GaN RTD-like heterostructures

J. Lee, Q. Fan, X. Ni, U. Ozgur, V. Litvinov, H. Morkoç

Proceedings Volume 7216, 72160S (2009) https://doi.org/10.1117/12.809435

KEYWORDS: Gallium nitride, Aluminum nitride, Heterojunctions, Doping, Resistance, Epitaxial lateral overgrowth, Quantum wells, Metalorganic chemical vapor deposition, Reactive ion etching, Polarization

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Proceedings Article | 12 February 2009 Paper

Effect of thermal annealing on Cu-related green luminescence in ZnO

V. Avrutin, M. Reshchikov, N. Izyumskaya, R. Shimada, S. Novak, H. Morkoç

Proceedings Volume 7217, 72170X (2009) https://doi.org/10.1117/12.809477

KEYWORDS: Zinc oxide, Annealing, Copper, Thermal effects, Excitons, Luminescence, Aluminum, Temperature metrology, Quantum efficiency, Zinc

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Proceedings Article | 28 February 2008 Paper

Piezoelectric quantum 1/f noise in nitride-based heterostructures

Peter Handel, Hadis Morkoc, Engkee Sia, Amanda Truong

Proceedings Volume 6894, 68941N (2008) https://doi.org/10.1117/12.762387

KEYWORDS: Phonons, Gallium nitride, Acoustics, Scattering, Polarons, Semiconductors, Particles, Magnetism, Heterojunctions, Infrared radiation

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Proceedings Article | 28 February 2008 Paper

Comparison of various gate dielectrics on the performance of AlGaN/GaN HFETS

Qian Fan, Jacob Leach, Mo Wu, Bo Xiao, Xing Gu, Hadis Morkoç, Peter Handel

Proceedings Volume 6894, 689426 (2008) https://doi.org/10.1117/12.763688

KEYWORDS: Dielectrics, Ferroelectric materials, Silica, Zirconium dioxide, Transistors, Heterojunctions, Gallium nitride, Plasma enhanced chemical vapor deposition, Capacitance, Crystals

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Proceedings Article | 28 February 2008 Paper

Epitaxial lateral overgrowth of (11¯00) m-plane GaN on m-plane 6H-SiC by metalorganic chemical vapor deposition

X. Ni, Ü. Özgür, S. Chevtchenko, J. Nie, H. Morkoç, R. Devaty, W. Choyke

Proceedings Volume 6894, 689420 (2008) https://doi.org/10.1117/12.763848

KEYWORDS: Gallium nitride, Epitaxial lateral overgrowth, Silicon carbide, Metalorganic chemical vapor deposition, Scanning electron microscopy, Atomic force microscopy, Luminescence, Aluminum nitride, X-ray diffraction, Polarization

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Proceedings Article | 15 February 2008 Paper

Optical properties of polar, nonpolar, and semipolar InGaN/GaN multiple quantum wells on sapphire

X. Ni, R. Shimada, J. Leach, J. Xie, Ü. Özgür, H. Morkoç

Proceedings Volume 6894, 689428 (2008) https://doi.org/10.1117/12.763260

KEYWORDS: Gallium nitride, Quantum wells, Epitaxial lateral overgrowth, Polarization, Sapphire, Optical properties, Quantum efficiency, Metalorganic chemical vapor deposition, Luminescence, Scanning electron microscopy

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The polarization fields in the c-axis-oriented hexagonal GaN system cause spatial separation of electrons and holes in quantum wells, reducing the quantum efficiency, and resulting in a red shift of the emission as well as a blue shift with increasing injected carrier density. In this paper, we report on the growth and optical characterization of InGaN/GaN multiple quantum wells (MQWs) on nonpolar (112¯0) a- and polar (0001) c-planes, as well as two semipolar planes, (112¯2) and (11¯01) of GaN. There are two kinds of a-plane used in this study. One of the (112¯0) a-planes was obtained on (11¯00) m-plane sapphire substrates during the epitaxial lateral overgrowth (ELO) of (112¯2) oriented semipolar GaN films, while the other one was planar a-plane GaN which was grown on (11¯01) r-plane sapphire substrates. The semipolar (112¯2) and (11¯01) planes were obtained as sidewall facets during the ELO of c-plane GaN with the mask stripes aligned along the GaN m-axis and a-axis, respectively. InGaN/GaN multiple quantum wells (MQWs) with a nominal well thickness of 4 nm and a barrier thickness of 8 nm were grown on these five GaN samples by metalorganic chemical vapor deposition. Excitation power dependent photoluminescence (PL) measurements were carried out on these quantum well structures to study the effect of polarization-induced electric field on the band-edge emission. The quantum-well emission energy from the two a-plane MQWs showed zero shift, compared to a 74 meV blue shift for the c-plane MQWs when the excitation power was increased from 1.3 mW to 37.0 mW. The semipolar (112¯2) showed a blue shift of 35 meV with increased excitation power, suggesting reduced polarization compared to that of c-plane. No quantum-well emission could be observed for the MQWs on (11¯01) semipolar planes. The shift in the quantum-well emission energy was attributed to the change of the screening effect of photon-generated carriers in the quantum wells at different excitation powers. For exact notation please see manuscript

Proceedings Article | 15 February 2008 Paper

AlxIn1-xN/GaN heterostructure field effect transistors

J. Xie, X. Ni, M. Wu, J. Leach, Ü. Özgür, H. Morkoç

Proceedings Volume 6894, 68941R (2008) https://doi.org/10.1117/12.771297

KEYWORDS: Aluminum nitride, Gallium nitride, Heterojunctions, Aluminum, Indium, Field effect transistors, Polarization, Metalorganic chemical vapor deposition, Temperature metrology, Scattering

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Proceedings Article | 15 February 2008 Paper

Spin-orbit coupling in AlGaN/AlN/GaN heterostructures with a polarization induced two-dimensional electron gas

Ç. Kurdak, H. Cheng, N. Biyikli, Ü. Özgür, H. Morkoç, V. Litvinov

Proceedings Volume 6894, 68940M (2008) https://doi.org/10.1117/12.763181

KEYWORDS: Heterojunctions, Magnetism, Aluminum, Gallium nitride, Phase measurement, Crystals, Polarization, Semiconductors, Spintronics, Magnetic semiconductors

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Proceedings Article | 15 February 2008 Paper

Comparative study of deep levels in GaN grown on different templates

J. Nie, S. Chevtchenko, J. Xie, X. Ni, H. Morkoç

Proceedings Volume 6894, 689424 (2008) https://doi.org/10.1117/12.767834

KEYWORDS: Gallium nitride, Epitaxial lateral overgrowth, Spectroscopy, Capacitance, Sapphire, Temperature metrology, Metalorganic chemical vapor deposition, Diodes, Active optics, Thermography

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Proceedings Article | 15 February 2008 Paper

GaN Schottky barrier and metal-semiconductor-metal photodetectors with in situ SiNx nano-network

J. Xie, J. Mateo, Ü. Özgür, H. Morkoç

Proceedings Volume 6894, 68941S (2008) https://doi.org/10.1117/12.764245

KEYWORDS: Gallium nitride, Photodetectors, Metalorganic chemical vapor deposition, Sensors, Ultraviolet detectors, Diodes, Epitaxial lateral overgrowth, Gold, Silicon, Sapphire

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Proceedings Article | 15 February 2008 Paper

ZnO hybrid microcavities grown by plasma assisted molecular beam epitaxy

Ryoko Shimada, Jinqiao Xie, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç

Proceedings Volume 6895, 68950I (2008) https://doi.org/10.1117/12.762299

KEYWORDS: Polaritons, Zinc oxide, Reflectivity, Excitons, Optical microcavities, Photons, Molecular beam epitaxy, Aluminum, Interfaces, Plasma

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Proceedings Article | 15 February 2008 Paper

Investigation of charge trapping at the oxide/semiconductor interface for MBE-grown GaN films

J. Moore, M. Reshchikov, J. Ortiz, J. Xie, H. Morkoç, A. Baski

Proceedings Volume 6894, 68940B (2008) https://doi.org/10.1117/12.768041

KEYWORDS: Gallium nitride, Electrons, Interfaces, Ultraviolet radiation, Oxides, Metalorganic chemical vapor deposition, Atomic force microscopy, Microscopy, Semiconductors, Gallium

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Proceedings Article | 15 February 2008 Paper

Effect of ion damage on optical properties of ZnO films grown by plasma-assisted MBE

V. Avrutin, M. Reshchikov, J. Nie, N. Izyumskaya, R. Shimada, Ü. Özgür, J. Foreman, H. Everitt, C. Litton, H. Morkoç

Proceedings Volume 6895, 68950Y (2008) https://doi.org/10.1117/12.764132

KEYWORDS: Ions, Zinc oxide, Sapphire, Plasma, Oxygen, Luminescence, Optical properties, Molecular beam epitaxy, Control systems, Excitons

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Proceedings Article | 15 February 2008 Paper

Use of quantum 1/f noise formulas in the reliability characterization of nitride-based heterostructures

Peter Handel, Hadis Morkoç, Amanda Truong

Proceedings Volume 6894, 68941K (2008) https://doi.org/10.1117/12.764083

KEYWORDS: Scattering, Field effect transistors, Reliability, Quantum physics, Heterojunctions, Diffusion, Quantum wells, Infrared radiation, Quantum well infrared photodetectors, Photodetectors

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Proceedings Article | 15 February 2008 Paper

Evolution of surface morphology of polar and nonpolar GaN thin films during photoelectrochemical etching

J. Leach, Ü. Özgür, X. Ni, J. Xie, H. Morkoç

Proceedings Volume 6894, 689425 (2008) https://doi.org/10.1117/12.762383

KEYWORDS: Etching, Gallium nitride, Epitaxial lateral overgrowth, Scanning electron microscopy, Thin films, Nanostructures, Transmission electron microscopy, Ions, Oxides, Active optics

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Proceedings Article | 15 February 2008 Paper

AlGaN/SiC heterojunction bipolar transistor

Ya. Alivov, Q. Fan, X. Ni, S. Chevtchenko, I. Bhat, H. Morkoç

Proceedings Volume 6894, 68941W (2008) https://doi.org/10.1117/12.763143

KEYWORDS: Heterojunctions, Transistors, Silicon carbide, Gallium nitride, Aluminum, Metalorganic chemical vapor deposition, Diodes, Doping, Gallium, Electrical engineering

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Proceedings Article | 20 February 2007 Paper

Electrical characteristics of n-ZnO/n-6H-SiC heterostructures grown by rf-sputtering

Ya. Alivov, B. Xiao, Q. Fan, D. Johnstone, C. Litton, H. Morkoç

Proceedings Volume 6474, 64740F (2007) https://doi.org/10.1117/12.713217

KEYWORDS: Zinc oxide, Heterojunctions, Silicon carbide, Diodes, Temperature metrology, Spectroscopes, Spectroscopy, Light emitting diodes, Capacitance, Fluctuations and noise

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Proceedings Article | 20 February 2007 Paper

Carrier relaxation and stimulated emission in ZnO nanorods grown by catalyst-assisted vapor transport on various substrates

V. Avrutin, Ü. Özgür, N. Izyumskaya, S. Chevtchenko, J. Leach, J. Moore, A. Baski, C. Litton, H. Everitt, K. Tsen, M. Abouzaid, P. Ruterana, H. Morkoç

Proceedings Volume 6474, 64741M (2007) https://doi.org/10.1117/12.708835

KEYWORDS: Zinc oxide, Silicon, Near field scanning optical microscopy, Atomic force microscopy, Luminescence, Transmission electron microscopy, Gallium nitride, Raman spectroscopy, Nanostructures, Nanorods

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Proceedings Article | 20 February 2007 Paper

Influence of annealing in oxygen ambient on crystal properties of rf-sputtered PZT layers on ZnO substrates

Ya. Alivov, F. Agra, B. Xiao, S. Chevtchenko, C. Litton, H. Morkoç

Proceedings Volume 6474, 64741B (2007) https://doi.org/10.1117/12.706506

KEYWORDS: Ferroelectric materials, Annealing, Zinc oxide, Crystals, Oxygen, Atomic force microscopy, X-ray diffraction, Bridges, Temperature metrology, Perovskite

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