The temperature variation of the A-center (a cadmium-vacancy halogen-donor pair) luminescence has been calculated using a temperature-dependent electron-ion interaction. The photoluminescence lines of the A center show a pronounced shift with temperature between 4 and 50 K. The zero-phonon line is explained in terms of a donor-acceptor pair transition and the temperature dependence is not due to the thermal expansion of the CdTe crystal. It results from excitations of electrons from shallow levels of isolated halogen donors and from transitions from the conduction-band edge to the deep acceptor level of the A center.

• Received 7 December 1992

DOI:https://doi.org/10.1103/PhysRevB.48.11726