A detailed numerical description of the free-electron concentration and mobility due to charged dislocation lines was presented. The scattering at dislocations was numerically analyzed in addition to the other scattering mechanisms and the transverse mobility was calculated by the energy averaging technique. Furthermore, the effect on mobility from an unintentional bulk acceptor concentration was calculated at room temperature. Specifically the calculated mobility was presented as a function of the combined effect from free electrons (1015–1019/cm3), dislocations (5 x 108–1012/cm2), and bulk acceptors (1015–1019/cm3). Also compensation from 0 to 100% was considered. Results were compared with experimental mobility data. Most mobility results in epitaxially grown GaN layers intended for optical and electronic device structures were limited by ~1010/cm2 dislocations and a compensation which was typically 30 to 60%.

Mobility in Epitaxial GaN - Limitations of Free-Electron Concentration due to Dislocations and Compensation. M.N.Gurusinghe, T.G.Andersson: Physical Review B, 67[23], 235208 (7pp)