Investigation of the electrical activity of V-defects in GaN using scanning force microscopy

André Lochthofen; Wolfgang Mertin; Gerd Bacher; Lutz Hoeppel; Stefan Bader; Jürgen Off; Berthold Hahn

doi:10.1117/12.808992

16 February 2009 Investigation of the electrical activity of V-defects in GaN using scanning force microscopy

André Lochthofen, Wolfgang Mertin, Gerd Bacher, Lutz Hoeppel, Stefan Bader, Jürgen Off, Berthold Hahn

Proceedings Volume 7216, Gallium Nitride Materials and Devices IV; 721610 (2009) https://doi.org/10.1117/12.808992
Event: SPIE OPTO: Integrated Optoelectronic Devices, 2009, San Jose, California, United States

Abstract

We report on the characterization of V-defects in GaN-based heterostructures via scanning force microscopy techniques. The diameter and density of the V-defects are found to strongly depend on growth thickness and temperature of the top layer, respectively, while no correlation between the V-defect formation and the type of doping could be identified. Kelvin probe force microscopy measurements revealed for both, n- and p-doped GaN top layers, a decrease of the Kelvin voltage within the V-defects, which indicates an enhanced work function of the facets of the V-defects with respect to the planar surface. Surprisingly, an increase of the current flow within the V-defects is found by conductive atomic force microscopy in case of the n-doped top layer, while current flow into the V-defect is suppressed for the p-doped top layer. For a consistent explanation of these results we suggest a model, which is based on an enhanced electron affinity of the {10-11}-surfaces within the V-defects as compared to the planar (0001)-surface.

Citation Download Citation

André Lochthofen, Wolfgang Mertin, Gerd Bacher, Lutz Hoeppel, Stefan Bader, Jürgen Off, and Berthold Hahn "Investigation of the electrical activity of V-defects in GaN using scanning force microscopy", Proc. SPIE 7216, Gallium Nitride Materials and Devices IV, 721610 (16 February 2009); https://doi.org/10.1117/12.808992

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