Band gap energy and exciton peak of cubic CdS/GaAs epilayers

Cubic zinc blende CdS epilayers were grown on (100) GaAs substrates by hot-wall epitaxy. The lattice constant of cubic CdS was measured by x-ray diffraction and it was found that the compressive strain remained in the CdS films. Photoluminescence (PL) measurement showed the free exciton emission at the room temperature. Room temperature energy gap and exciton binding energy were determined by absorption and PL spectra.