OPTICAL AND MAGNETOOPTICAL STUDY OF PHOTOREFRACTIVE GERMANIUM-DOPED CADMIUM TELLURIDE

A photorefractive CdTe:Ge single crystal was investigated via photo-ab sorption at room temperature, 98 K and 4.3 K, and magnetic circular di chroism at 1.4 K. At all wavelengths, except near 1064 nm, absorption spectra suffer relatively large changes under various illuminations. M agnetic circular dichroism demonstrates unambiguously the presence of two paramagnetic defects, one of them being the ionised donor Ge+ at t he Cd site. Our results further reveal the existence of four absorptio n components around 0.94 eV, 1.10 eV, 1.22 eV and 1.36 eV. The two ext reme ones are assigned to the photoneutralisation of Ge-Cd(+) and to t he photoionisation of Ge-Cd(0) respectively. (C) 1998 Elsevier Science B.V. All rights reserved.