Charge transfer in photorefractive CdTe : Ge at different wavelengths

The charge transfer processes in photorefractive CdTe:Ge were modeled using the data of optical absorption, magnetic circular dichroism (MCD) and elec tron paramagnetic resonance (EPR) spectroscopies. Within the developed mode l the variations in the photorefractive properties of different CdTe:Ge sam ples are explained by differences in the relative concentrations of donor a nd trap centers. The existence of two different centers of comparable conce ntrations, each in two charge states, allows charge redistribution between them and gives rise to optical sensitization of some CdTe:Ge samples for ph otorefractive recording under an auxiliary illumination. In the present art icle we follow the proposal of pseudo-3D presentation of light-induced abso rption to distinguish the main charge transfer processes at different excit ation energies and explain the sensitization of CdTe:Ge for photorefractive recording at 1.06, 1.32 and 1.55 mum by light with appropriate wavelength. (C) 2001 Elsevier Science B.V. All rights reserved.