Relaxation of photoconductivity in nanocrystalline indium oxide

Photoelectric properties of nanocrystalline indium oxide synthesized by the sol-gel method with nanocrystal sizes of 7–20 nm have been studied. An increase in the conductance by UV-light illumination of several orders of magnitude and the retention of this high-conducting state after the light is switched off is revealed. The kinetics of photoconductivity decay in air, vacuum, and argon at room temperature is studied; it is found that the photoconductivity decay is described by an expanded exponent. A conclusion about the determining role of oxygen molecules in the phenomenon of residual photoconductivity is made. A model is proposed which explains permanent photoconductivity decay in nanocrystalline indium oxide. A correlation between structural and photoelectric features in the object under study is found.