Photoluminescence and photoacoustic spectra of ZnSe bulk crystals and epitaxial layers

Temperature dependence of the piezoelectric photoacoustic (PPA) and photoluminescence (PL) spectra are clearly observed between liquid helium and room temperatures for nondoped ZnSe bulk crystals and epitaxial layers. In both samples, the PPA signals are clearly observed at room temperature. However, any PL emissions are not observed at room temperature. Two kinds of recombination processes, i.e., both radiative and nonradiative processes are observed at 80 K in the bulk crystals.