Energy structure and micromechanism of photo-EMF effect in adaptive IR-detectors based on CdTe:V crystals

Abstract

For the first time the photo-EMF measurements were carried out for CdTe crystals doped with V atoms as a result of the photogeneration of carriers from deep impurity centers to the conduction band and the tilted geometry was applied that allowed two-mentional monitoring of the vibration source. The CdTe:V crystals were excited by a He-Ne laser with λ=1.15 µm (ħω=1.08 eV) and P=2 mW. The mechanism of appearance of the holographic current in the CdTe:V crystals (adaptive IR-photodetectors) taking into account of real defect structure was proposed. The frequency dependence of ac photo-EMF (holographic) current for the CdTe:V crystal was measured. It was shown that a low cutoff frequency for the laser intensity I=0.2 mW/mm 2 equals 6.0 kHz that corresponds to the response time of 26 µsec.