Crystal-orientation dependence of photoconductivity in Pb₂CrO₅ thin film

Abstract

Crystal-orientation dependence in photoconductive Pb₂CrO₅ thin film devices, prepared by an electron-beam evaporation deposition technique, with interdigital electrodes is described as functions of film thicknesses, temperature, and electrode widths. There are three types of orientations of (020), (310), and (200). The photoconductive sensitivity of (200) is smaller than the other orientations because of the lower carrier mobility. The observed activation energy for each oriented sample is 0.69 or 0.26 eV for the dark or the photoillumination state. The film thickness influences strongly the photoconductive sensitivity and spectrum. At the shorter wavelengths the difference of the photoconductive current due to the illumination direction is obvious. The ratio of the finger width to the gap of interdigital electrodes on the thin film affects the photoconductive current level without changing the photoconductive spectra.