Fano resonance study in impurity photocurrent spectra of bulk GaAs and GaAs quantum wells doped with shallow donors

The results of theoretical and experimental study of the impurity photocurrent peaks in the spectral region corresponding to the longitudinal optical phonon energy in bulk GaAs and GaAs quantum wells doped with silicon are presented. The general expression to describe these impurity photocurrent peaks is derived. It is shown that the suggested theory adequately describes the impurity photocurrent peaks observed in bulk GaAs. We demonstrate that the photocurrent peak width in a quantum well structure is greater than that in a bulk semiconductor.