Edge and Donor-Acceptor Pair Emissions in Cadmium Telluride

Abstract

The luminescent properties of the edge and 1.42 eV emission bands in CdTe single crystals have been investigated in the temperature range from 140 to 4.2 K. Two distinct edge emission spectra (1.545 and 1.528 eV bands) are found in as-grown p-type crystals depending on crystal growth conditions. The time-resolved spectra and the dependence on the excitation intensity of the photoluminescence confirm that the 1.42 eV band which is usually observed in both n- and p-type CdTe is associated with transitions between donors and acceptors. The values of the ionization energy of donors and acceptors and some parameters involved in the pair emission are estimated.