Improvement of luminescence properties of InN by optimization of multi-step deposition on sapphire

Thin films of InN were grown on sapphire by metalorganic chemical vapor deposition using multi-step growth technique (thermal cleaning and nitridation of sapphire substrate, deposition and annealing of nucleation layer, and growth of the active InN layer). The effects of different growth steps on the structural quality and luminescence properties of the samples grown for the study were analyzed by X-ray structural analysis (ω-2Θ scans, measurement of rocking curves) and photoluminescence spectroscopy with sub-micrometer spatial resolution enabled by applying confocal microscopy. The influence of nitridation duration, variation of thickness and annealing conditions of nucleation layer, and the temperature of deposition of the active InN layer were studied and discussed.