Two-dimensional electron gas transport anisotropy in N-polar GaN/AlGaN heterostructures

Magnetic-field dependent Hall-effect measurements and mobility spectrum analysis were employed to study anisotropic transport in N-polarGaN/Al(0.3)Ga(0.7)N heterostructures grown on vicinal sapphire substrates. The significant anisotropy in the mobility in the parallel and perpendicular directions to the miscut direction was accompanied by a slight anisotropy in charge density. A single electron species was found in the direction parallel to the steps resulting from growth on the vicinal substrates; while in the perpendicular direction two distinct electrons peaks were evident at T <= 150 K. The lower average mobility in the perpendicular direction is attributed to interface roughness scattering. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3595341]