Photoluminescence of ZnTe crystals grown under deviation from thermodynamic equilibrium

Crystalline textured and columnar structures, as well as needlelike ZnTe single crystals, were grown from the vapor phase and in a tellurium melt under deviation of the growth conditions from equilibrium. Low-temperature photoluminescence and x-ray structural studies showed the samples thus grown to exhibit high structural perfection, a uniform impurity distribution, and weak interaction between impurities and defects of the crystal structure. Polariton scattering from neutral donors was detected in structures having a noticeable residual concentration of donors in the substituted state. It is shown that the spectrum of samples grown under nonequilibrium conditions exhibits transitions that are not typical of equilibrium crystals. Measurements of the luminescence spectra as a function of temperature, excitation level, and annealing conditions made it possible to draw tentative conclusions about the nature of these transitions.