High-electron-mobility GaN grown on free-standing GaN templates by ammonia-based molecular beam epitaxy
Journal
Journal of Applied Physics
Journal Volume
115
Journal Issue
19
Date Issued
2014
Author(s)
Abstract
The dependence of electron mobility on growth conditions and threading dislocation density (TDD) was studied for n--GaN layers grown by ammonia-based molecular beam epitaxy. Electron mobility was found to strongly depend on TDD, growth temperature, and Si-doping concentration. Temperature-dependent Hall data were fit to established transport and charge-balance equations. Dislocation scattering was analyzed over a wide range of TDDs (∼2 × 106 cm-2 to ∼2 × 10 10 cm-2) on GaN films grown under similar conditions. A correlation between TDD and fitted acceptor states was observed, corresponding to an acceptor state for almost every c lattice translation along each threading dislocation. Optimized GaN growth on free-standing GaN templates with a low TDD (∼2 × 106 cm-2) resulted in electron mobilities of 1265 cm2/Vs at 296 K and 3327 cm2/Vs at 113 K. © 2014 AIP Publishing LLC.
Type
journal article