Influence of zinc on the photorefractive behaviour of Cd1−xZnxTe:V

Abstract Recent studies of the photorefractive characteristics of CdTe:V compound have demonstrated this material to provide high two wave mixing gain in the 1–1.5 μm wavelength range. However due to its high figure of merit, larger two wave mixing gain could be expected. We present some results about the influence of the zinc content in these materials which could explain such a reduction. In particular, we show that crystals can be ranked in two different classes following their photorefractive properties. This classification is essentially based on the absence (or existence) of a resonant intensity-temperature effect with the crystals with zinc (respectively without zinc). We also present some physico-chemical parameters obtained on these crystals by secondary ionic mass spectroscopy (SIMS) and electron paramagnetic resonance (EPR) experiments. The difference of photorefractive properties between the two classes would imply an evolution in the V 2+ V 3+ ratio which is not 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.