Cathodoluminescence and isochronal annealing investigations of edge-emission in ZnTe

Investigation of the liquid helium temperature cathodoluminescence edge-emission of undoped ZnTe has shown that two bands at 545.8 and 547.3 nm result respectively from free-to-bound and donor-acceptor pair recombination at a common acceptor level with a hole binding energy of 124 meV. From observations of the changes that occur in the edge-emission spectrum after isochronal (30 min) annealing treatments in vacuum in the temperature range 50–500°C it is suggested either that the acceptor defect is mobile and can move out of sites at which it behaves as an acceptor to sites at which it behaves as a donor or, during annealing complexing occurs which changes the nature of the centre and effectively removes it.