Photodetectors for visible and near infra-red region with controlled sensitivity on the basis of p-GaSe single crystals doped by rare-earth elements

Abstract

Under various external conditions the features of initial and sensitized photoconductivity in p-GaSe with NREE ≈ 0÷10-1 at. % have been investigated. It is established that in the initial state investigated crystals possess photosensitivity only in the intrinsicl absorption region, photoelectric threshold and a relaxation velocity vary with change of NREE. Under the influence by intrinsic highlight with relatively high intensity, or an external electric voltage (U) greater some critical value, investigated samples acquire photosensitivity also in the impurity region. It is supposed that the sensitization of the impurity photoconductivity in this material is connected to presence in the forbidden band of shallow trapping levels which concentration grows with increasing NREE. The opportunity of the creation of highly stable photodetectors for visible and near IR irradiation with controlled sensitivity on the base of p-GaSe crystals has been shown.