Direct Current in Non-steady-state Photovoltaic Effect

A new non-steady-state photovoltaic effect in a uniform bipolar semiconductor doped with impurities changing their charge state under illumination is predicted. Direct electric current is shown to arise in the ring-shaped uniform bipolar semiconductor sample illuminated by a moving light pattern. The physical basis of the effect is the simultaneous change of the charge carriers density and mobility, as well as the difference in lifetimes of the ionized impurities, charge carriers and the light pattern traveling time along the semiconductor sample.