Room Temperature Photoluminescence in CdTe Grown by Liquinert-Processed Vertical Bridgman Method

Bulk CdTe samples were grown by a liquinert-processed vertical Bridgman method to reduce the influence of a crucible wall. We observed near-band-gap photoluminescence in the samples at 300K. The peak around 1.5eV whose origin has been controversial for three decades is assigned to the recombination between a free electron and an acceptor-bound hole. We estimate the ionization energy of the acceptor to be 26meV. High concentrations of the acceptors are responsible for the reason why shallow acceptors are not ionized at room temperature.