Ballistic photoconductivity in nanostructures

A model for photoconductivity of nanostructures, in which carriers move col lisionlessly between electrodes or regions of intensive recombination, is p resented. Detailed analysis was performed for two particular cases: a thin film between two bulk contacts and low-temperature grown GaAs containing As clusters. The photocurrent dependence on the applied voltage V was found t o be essentially nonlinear for small V and tend to saturation for large V. The spectrum of photoconductivity differs drastically from that of optical absorption and is characterized by a maximum near the absorption edge, with peak position depending on V. (C) 2001 American Institute of Physics.