Influence of Space Charge and Potential Fluctuations on Photoconductivity Spectra of Semiinsulating CdTe

The influence of polarization effects on room temperature photoconductivity spectra of high-resistivity CdTe was investigated. It was shown, that space charge accumulated on deep levels can result in a different energy position of the main photoconductivity maximum at opposite polarities of the applied electric field. The shift of the main photoconductivity maximum to lower energies with an applied electric field at 10 K was observed. Explanation of this phenomenon could be in inclination of band gap in applied electric field. This leads to increasing probability of liberation of carriers from potential minima existing in the material due to various types of fluctuations to the bands.