Photoconductive response of polycrystalline Cu0.5Ag0.5InSe2 thin films

Photoconductivity response spectra of polycrystalline Cu0.5Ag0.5InSe2 thin films are reported. The peak and shoulders observed in the photoconductivit y spectra are attributed to transitions from valence sub-bands to the condu ction band. From the room-temperature spectra, the band-gap energies, spin- orbit and crystal-field parameters are determined. The temperature coeffici ent of the photoconductivity peak energy is 1.25 x 10(-4) eV K-1 in the tem perature range 60-100 K. The sign of the temperature coefficient reverses a round 100 K and the value is -1.23 x 10(-4) eV K-1 in the temperature range 100-303 K. The variations of photocurrent with applied bias voltage, illum ination intensity and temperature are also studied. (C) 2001 Kluwer Academi c Publishers.