Free-exciton photoluminescence from cubic CdS films on GaAs substrates

We have studied optical properties of cubic CdS thin films for various temperatures by means of picosecond time-resolved photoluminescence (PL) and photoreflectance (PR) spectroscopy. Optical transitions due to heavy-hole (HH) and light-hole (LH) excitons are observed in the PR spectrum. Two PL peaks due to the HH and LH excitons are observed in picosecond time-resolved PL spectrum. The temperature dependence of the PL energy and the PL line width for cubic CdS is determined.