Abstract: A thin film of copper phthalocyanine (CuPc) a p-type semiconductor was deposited by thermal evaporation in vacuum on an n-type gallium arsenide (GaAs) single-crystal semiconductor substrate. Then semitransparent Ag thin film was deposited on to the CuPc film also by thermal evaporation to fabricate the Ag/n-GaAs/p-CuPc/Ag cell. Photoconduction of the cell was measured in photoresistive and photodiode modes of operation. It was observed that with increase of illumination the photoresistance decreased in reverse bias while it increased in forward bias. The photocurrent was increased in reverse bias operation. In forward bias operation with increase of illumination the photocurrent showed a different behavior depending on the voltage applied.

Key words: Organic-inorganic,  thin film,  photoconductive cell,  copper phthalocyanine,  gallium arsenide