Donor-related edge luminescence in ion-implanted ZnTe

Single crystal samples of ZnTe are implanted at 77 K with chlorine, bromine, copper, or silver ions of 100 keV energy. The low temperature cathodoluminescence spectra of the sample are recorded as a function of post-implantation isochronal (30 min) annealing temperature in vacuum in the range 50 to 500 0C and compared with the spectra of similarly-annealed unimplanted and argon-implanted reference samples. Chlorine, bromine, and copper each induce similar changes in the emission spectrum and, in addition to enhancing strongly donor-acceptor pair bands at 547.3 (C/sub II/) and 553.6 nm (B/sub II/), produced new edge emission bands at 530.2, 535.2, and 530.6 nm, respectively. These three new bands are each assigned to a transition from a deep donor level to the valence band. The deep donor defects are attributed to the complexes (V/sub Zn/2Cl/sub Te/), (V/sub Zn/2Br/sub Te/), and (V/sub Zn/2Cu/sub i/) or (V/sub Zn/2Cu/sub Te/), with electron binding energies of 65, 88, and 69 meV, respectively. In contrast, annealing of silver-implanted ZnTe causes emission spectrum changes comparable to those induced by argon ion bombardment and produces no effects which can be attributed to the silver impurity. (author)