Single crystal growth and optical energy gap of gallium telluride

A single crystal of GaTe was prepared by the modified Bridgman technique method. The interband absorption coefficients were measured, near the fundamental absorption edge, as a function of the wavelength of the incident photons at various temperatures. Based on the three-and two-dimensional models, the results were discussed. The optical energy gap was determined to be 1.57 eV from these models. The temperature dependence of the optical energy gap was studied from 360 K to near liquid nitrogen temperature. This dependence was found to be linear in the temperature range of investigation with a negative temperature coefficient dE(g)/dT equal to -4.5 x 10(-4) eV/K (+/-1%) for both the three and two-dimensional models. (C) 2000 Elsevier Science Ltd. All rights reserved.