Recombination processes in CuInS₂/ZnS nanocrystals during steady-state photoluminescence

We report on a temperature- and excitation-power-dependent photoluminescence (PL) study of CuInS₂/ZnS nanocrystals dispersed on a SiO₂/Si substrate with a confocal micro-PL system. With increasing the excitation power at 22 K and room temperature, the PL spectra are blue-shifted because of the state filling. At low temperature, a small peak is observed at the low energy side of the spectrum, which could be due to the Förster resonance energy transfer between different nanocrystals. The integrated PL intensity increases sublinearly as a function of excitation power with a power factor of around 2/3, which demonstrates the Auger recombination dominated process in the nanocrystals, especially under the high excitation power.