DEPENDENCE OF THE OPTICAL-PROPERTIES OF P-CDTE AND P-CD0.96ZN0.04TE ON THE BROMINE CONCENTRATION IN A BROMINE-METHANOL ETCHING SOLUTION

Photoluminescence measurements were carried out to investigate the dep endence of the optical properties of p-CdTe and p-Cd0.96Zn0.04Te on va rious relative concentrations of bromine in a mixture of methanol and bromine. As the bromine concentration increased, the intensity of the luminescence increased; additionally, an exciton bound to a neutral ac ceptor (A-degrees X) peak at 1.588 eV in p-CdTe was resolved into an e xciton bound to neutral donor (D-degrees X) peak at 1.592 eV and an A- degrees X peak. The mixed bands of the 1.574 and 1.546 eV peaks were w ell resolved by using an etching bromine concentration of 2%; in parti cular, the intensities of the D-degrees X and 1.574 eV peaks increased as much as five and seven times, respectively. The intensity of the p eak at 1.48 eV related to defects also increased. The intensity of A-d egrees X at 1.609 eV in p-Cd0.96Zn0.04Te changed slightly with the bro mine concentration. The intensities of the luminescence peaks due to t he recombination of the electrons in conduction band with acceptors an d to the defect relation did not vary. These results indicated that th e number of Cd vacancies could be reduced due to the addition of Zn.