Recombination processes in CuInS${}_2$/ZnS Nanocrystals during steady-state photoluminescence

Abstract

We report on temperature- and excitation-power-dependent photoluminescence (PL) study of CuInS${}_2$/ZnS nanocrystals dispersed on a SiO${}_2$/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 F$\ddot{o}$rster 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.

12 pages, 3 figures