Optical and electrical characterizations of In-doped GaN films grown by metalorganic vapor phase epitaxy

Isoelectronic In doping effects on GaN film have been studied in terms of electrical and optical properties. Our results indicate that the 15 K-photoluminescence linewidth of near-band-edge emission (I₂) is reduced from 16 to 10 meV with the incorporation of In. The corresponding recombination lifetime also drops immediately to a constant value, nearly independent of measured temperature and trimethylindium reactant supply. Regarding electrical properties, the ideality factor of an n-GaN Schottky diode is improved from 1.20 to 1.06, and the deep levels at 0.149 and 0.601 eV below the conduction band can also be effectively suppressed. This work clearly demonstrates that isoelectronic In doping is an effective and simple method for improving the GaN film quality.