High-mobility AlGaN/GaN heterostructures grown by molecular-beam epitaxy on GaN templates prepared by hydride vapor phase epitaxy

We report on the growth and transport properties of high-mobility two-dimen sional electron gases (2DEGs) confined at the AlGaN/GaN interface grown by plasma-assisted molecular-beam epitaxy on GaN templates prepared by hydride vapor phase epitaxy. We have grown samples over a broad range of electron densities ranging from n(s)=6.9x10(11) to 1.1x10(13) cm(-2), and at T=4.2 K , observe a peak mobility of 53 300 cm(2)/V s at a density of 2.8x10(12) cm (-2). Magnetotransport studies on these samples display exceptionally clean signatures of the quantum Hall effect. Our investigation of the dependence of 2DEG mobility on carrier concentration suggests that the low-temperatur e mobility in our AlGaN/GaN heterostructures is currently limited by the in terplay between charged dislocation scattering and interface roughness. (C) 2000 American Institute of Physics. [S0003-6951(00)05343-2].