Properties of Si-Doped a-Plane GaN Grown with Different SiH4 Flow Rates

Abstract

Nonpolar Si-doped a-plane GaN layers were grown using metal organic chemical vapor deposition (MOCVD) with different silane (SiH4) flow rates. The on-axis full width at half maximum (FWHM) of X-ray rocking curves (XRCs) along the c- and m-axis directions showed that Si doping barely affected the anisotropy of a-plane GaN. A decrease in the edge threading dislocations (TDs) with increasing Si doping was confirmed by the decreased off-axis FWHM values of the XRCs. With increasing SiH4 flow rate, both the carrier concentration and mobility increased through a reduction in the edge dislocation density. The photoluminescence (PL) spectra revealed that the PL peak positions were first slightly redshifted and then blueshifted with increasing carrier concentration.