In -rich In_1-x Ga_x N films by metalorganic vapor phase epitaxy

Single crystalline In1-x Gax N films containing high In content (70%-100%) were grown by metalorganic vapor phase epitaxy. A linear relation was observed between the lattice constants and gas phase GaIn ratios. The surface morphology changed from pyramid for InN to more planar ones for the InGaN alloys with increasing Ga content. The electron mobility decreased rapidly from 1200 cm2 V s for InN to less than 100 cm2 V s for In0.7 Ga0.3 N, with a carrier concentration of low- 1019 cm-3 for all the as-grown films. Using photoluminescence a single emission peak was observed at 1.4-1.6 μm for the In -rich InGaN with decreasing wavelengths up to below 20% of Ga. Two peaks were observed for the In0.80 Ga0.20 N, however, indicating possible phase separation. The x-ray photoelectron spectroscopic measurement showed shifts to higher binding energies for both In and Ga with increasing Ga content. The estimated alloy composition, however, depended sensitively on the sputtering conditions of the samples.