Optical characterization of quaternary Zn1-x-yBexMgySe mixed crystals

Abstract

We present an optical characterization of three Bridgman-grown Zn1-x-yBexMgySe mixed crystals in the near-band-edge interband transitions using temperature-dependent photoluminescence (PL), contactless electroreflectance (CER), and photoreflectance (PR) in the temperature range of 15–400 K and surface photovoltage spectroscopy (SPS) at room temperature. PL spectra at low temperature are characterized by the presence of clearly distinguished features, such as an excitonic line, an edge emission due to radiative recombination of shallow donor- acceptor pairs, and a broad band related to recombination through deep level defects. The peak positions of the excitonic emission lines in PL spectra correspond quite well to the energies of the fundamental transitions determined from CER, PR, and SPS measurements.