Depletion-Layer Photoeffects in Semiconductors

The theory of photoconduction through the reverse-biased $p\ensuremath{-}n$ junction in semiconductors is developed without the customary assumption that carrier generation in the junction depletion layer is negligible. Different from previous theories, the more general treatment leads to a voltage dependence of the photocurrent and its spectral distribution. When the incident light beam is modulated at frequencies comparable to the transit time through the depletion layer, a phase shift between the photon flux and photocurrent is noticed and transit-time rectification occurs.