INFLUENCE OF ZINC ON THE PHOTOREFRACTIVE BEHAVIOR OF CD1-XZNXTE-V

Recent studies of the photorefractive characteristics of CdTe:V compou nd have demonstrated this material to provide high two wave mixing gai n in the 1-1.5 mu m wavelength range. However due to its high figure o f merit, larger two wave mixing gain could be expected. We present som e results about the influence of the zinc content in these materials w hich could explain such a reduction. In particular, we show that cryst als can be ranked in two different classes following their photorefrac tive properties. This classification is essentially based on the absen ce (or existence) of a resonant intensity-temperature effect with the crystals with zinc (respectively without zinc). We also present some p hysico-chemical parameters obtained on these crystals by secondary ion ic mass spectroscopy (SIMS) and electron paramagnetic resonance (EPR) experiments. The difference of photorefractive properties between the two classes would imply an evolution in the V2-/V3+ ratio, which is no t compatible with the EPR results. As to clarify this problem we will propose a new model of two deep levels in the gap of the material.