At University of Oklahoma (OU), I have been involved with III-V InSb-based semiconductor research by molecular beam epitaxy (MBE) for applications of field-effect transistors, infrared detectors, and solar cells. I am an expertise of semiconductor nanostructures (epilayers, quantum wells, quantum dots) fabrication by MBE. I developed highest room-temperature(RT) electron mobility InSb epilayers (64,000 cm2/Vs) and quantum wells (24,000 cm2/Vs) on off-axis Ge(211) and Ge-On-Insulator-On-Si(001) substrates, respectively, for the first time. I also obtained uniform and high-density InSb QDs for efficient photovoltaic applications.

At AIST, Japan, I was involved with II-VI diluted magnetic semiconductor of (Cd,Mn)Te waveguide (both bulk and quantum well) growth by MBE for the highly efficient magneto-optical isolator in advanced optical communication systems. I developed (Cd,Mn)Te/(Cd,Zn)Te quantum well waveguide on GaAs(001) substrate for the first time, which showed complete mode conversion (100%) with wider operational wavelength range of 35 nm, very low optical loss of less than 0.2 dB/cm, high magneto-optical figure-of-merit of more than 2000 deg/dB/kG, and isolation ratio of more than 25 dB. Highly efficient (Cd,Mn)Te/Cd,Zn)Te quantum well demonstrate the feasibility of monolithically integrating an optical isolators with other semiconductor optoelectronic devices.

At Imperial College, London, UK, I worked on the III-V materials of InSb thin films for the spintronic and magneto-resistive sensor applications. The research works were focused on the high mobility InSb thin films for the practical device applications.

At JST and Tohoku University, in Japan, I was involved with several II-VI materials of ZnSe, ZnTe, CdTe and their compounds growth by MBE for understanding the basic physics and applications. . I developed homoepitaxy (Zn,Mn)Te/(Zn,Mg)Te spin superlattices, which is useful for spintronics devices, such as spin-transistor applications.