OPTICAL AND THERMAL SPECTROSCOPY OF VANADIUM-DOPED CDTE AND RELATED PHOTOREFRACTIVE EFFECT

The energy level diagram of substitutional vanadium in CdTe (and also Cd0.96Zn0.04Te) has been investigated by using a variety of optical an d thermal spectroscopy techniques: optical absorption, photoconductivi ty, photoluminescence, deep level optical spectroscopy, DLTS and therm ally stimulated current (PICTS). This study has led to set the V2+/V3 level at 0.95 eV below the conduction band with an optical photoioniz ation threshold at 1.03 eV. Two-wave mixing experiments were used to e valuate the photorefractive properties. Gain coefficients in excess of 10 cm-1 have been measured at lambda = 1.32 mum with applying a 40 Hz AC electric field.