The effects of isoelectronic in-doping in GaN films grown by MOCVD

Abstract

The isoelectronic In-doping effect in GaN films grown by metalorganic chemical vapor deposition (MOCVD) was investigated by using Raman scattering, scanning electron microscopy (SEM), Hall, Xray and photoluminescence (PL) measurements. In our study, after incorporating small amounts of In atoms into GaN compound (less than 0.4%, thus no alloy), SEM pictures showed improved surface smoothness with greatly reduced nano-pits, which was also confirmed by the multiple interference effects in PL spectra. Doping of adequate quantity caused the reduction of yellow luminescence and unintentional background concentration, and the line width shrinkage in X-ray, PL and Raman data, and the enhanced mobility. The improved crystalline and optical qualities of GaN:In films may be attributed to the decrease in dislocation density that may be related to the "impurity softening" phenomena.