Photoluminescence of CdTe grown on (001) InSb by molecular beam epitaxy

Abstract

CdTe films grown by molecular beam epitaxy on (001) InSb from a congruently subliming CdTe compound source were studied by photoluminescence for the presence of chemical impurities and native defects. Photoluminescence data taken at 77 K indicates that the optimum substrate growth temperature for a growth rate of 0.4 μm/h is about 170 °C. Negligible self-activated emission was observed at 77 and 6.5 K. The 6.5-K photoluminescence spectrum is dominated by edge emission at about 797 nm (∼1.55 eV) and this is attributed to recombination through acceptor impurity levels. Band-to-band recombination observed at room temperature and the presence of well-resolved free excitons as well as acceptor- and donor-bound excitons suggest the films are of high quality, but contain significant concentrations of donor and acceptor impurities.