Electron transport properties in Al0.25Ga0.75N/AIN/GaN hetrostructures with different InGaN back barrier layers and GaN channel thickness grown by MOCVD

Cataloged from PDF version of article.The electron transport properties in Al0.25Ga0.75N/AlN/GaN/InxGa1-xN/GaN double heterostructures with various indium compositions and GaN channel thicknesses were investigated. Samples were grown on c-plane sapphire substrates by MOCVD and evaluated using variable temperature Hall effect measurements. In order to understand the observed transport properties, various scattering mechanisms, such as acoustic phonon, optical phonon, interface roughness, background impurity, and alloy disorder, were included in the theoretical model that was applied to the temperature-dependent mobility data. It was found that low temperature (T 160 K), optical phonon scattering is the dominant scattering mechanism for AlGaN/AlN/GaN/InGaN/GaN heterostructures. The higher mobility of the structures with InGaN back barriers was attributed to the large conduction band discontinuity obtained at the channel/buffer interface, which leads to better electron confinement. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei