ON THE PHOTOVOLTAIC EFFECT IN BISMUTH OXIDE THIN FILMS

This work presents the investigation of photovoltaic effect in Al-Bi2O3-Al, Cu-Bi2O3-Cu and Al-Bi2O3-In2O3 sandwich structures. The bismuth oxide films have been prepared by thermal oxidation, in an oxygen-reach atmosphere, at ∼800K, of vacuum evaporated Bi films. From the spectral curves of photoconduction in respective structures, the energy gap values, Eg, of bismuth oxide films have been determined, by using the Moss criterion. By illumining the region of metal contacts, the electromotive force generated into the film always had positive polarity at semiconductor film. When a light source of A-type is used, the photoelectromotive force can reach 150 mV and actually doesn't depend on the metal nature. When the oxidation treatment in the same conditions (heating/cooling rates, upper temperature) is prolonged, the maximum of photosensitivity displaces towards UV region, together with diminution of integral sensitivity of the studied structures. The I-V characteristics of the mentioned structures have been also investigated