Electron Transport in MOVPE GaN Grown on Silicon Nitride Treated Sapphire

Abstract

Electron transport in GaN is of interest because of its importance in a range of electronic and optoelectronic devices. However, the intrinsic properties may be modified by the presence of scattering centres introduced either as a result of impurities or dislocations incorporated during growth. Here we analyse the transport properties of a GaN layer deposited on silicon nitride treated sapphire substrates which has a dislocation density in the low 108 cm—2 range. Temperature dependent Hall effect and resistivity data have been analysed using a two-band model including conduction band transport calculated using a relaxation time approximation and an iterative solution of the Boltzmann equation. A good fit has been obtained self-consistently to both the mobility and carrier density over a wide temperature range with no significant contribution from dislocation scattering.