Resonant excitation of space-charge and photoconductivity waves in semiconductors with shallow energy levels

We report resonant excitation of space-charge and photoconductivity waves in semiconductors with shallow energy levels. We predict the appearance of several resonance maxima in the frequency dependence of non-steady-state photocurrent excited in a semiconductor material. We show that both the effective and actual mobilities of photocarriers can be estimated from the characteristic resonant frequencies. Experimental measurements of the effective mobility are carried out in photorefractive n-type Bi₁₂SiO₂₀ grown in an argon atmosphere.