On the Theory of a Photocurrent Burst in an Intrinsic Photoresistor upon Longitudinal and Transverse Illumination

Resumo

In this paper, we analyze the intrinsic photoconductivity burst of semiconductors at an increase in the recombination center concentration upon uniform and non-uniform weak illumination along the electric field. An equation for the concentration distribution of nonequilibrium carriers at an arbitrary illumination profile along the electric field is derived without using the quasi-neutrality approximation. Based on this equation, the bursts in photoelectric gain of the transverse and longitudinal photoresistors should significantly differ from each other under any recombination conditions at current contacts due to the photo-induced space charge. If the carrier photogeneration is not uniform, then, unlike uniform photogeneration, the photoelectric gain burst depends on the polarity of the applied voltage. The quasi-neutrality approximation does not produce these results. An analytical expression for the maximum value of the electron photoelectric gain depending on the recombination center concentration is derived in the case of an exponential photogeneration profile and pulling-out contacts. The relationship that was found between the concentrations of nonequilibrium electrons and holes allows derivation of an analytical expression for the maximum value of the hole photoelectric gain.