PHOTOLUMINESCENCE OF CD1-XZNXTE CRYSTALS GROWN BY HIGH-PRESSURE BRIDGMAN TECHNIQUE

Photolumincscence (PL) spectra of detector-grade Cd1-xZnx Te crystals with x = 0.07 to 0.14 were measured as a function of the excitation la ser power and over the temperature range from 12 to 295 It. Two bound exciton transitions at the energies of 13 and 24 meV below the band-ga p E-g and a number of phonon replicas dominate the low-temperature PL spectra. The transition at the energy of E-g - 13 mcV is attributed to a neutral donor-bound exciton (DX)-X-0. The excitation power and temp erature dependence of the peak at the energy of E-g - 24 meV show that it is of excitonic origin with binding energy of 13 meV. The intensit y cf this A(0)X peak is found to depend on x, which suggests that it i s related to structural defects. In some samples a donor-acceptor pair (DAP) transition at the energy of E-g - 60 meV is observed. The PL sp ectra also exhibit a weak, defect-related broad peak at the energy of about E-g - 200 meV. The PL of a large number of samples from differen t boules and locations in the boules is compared. The DAP-peak intensi ty was observed to depend. strongly on the boule.