Electro-optical effects inInxGa1−xAs/GaAs strained-layer superlattices

The effect of electric fields on the optical spectra of strained-layer ${\mathrm{In}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As/GaAs superlattices is studied with use of the Schottky-barrier technique. Several well-resolved structures are observed in the photovoltaic spectra from 4.5 to 300 K. The spectral positions and widths of the structures—and, in the case of some structures, their very existence—were found to be influenced by low applied potentials. The combined effect of thermal energy and electrical field on the shape and magnitude of the spectra is discussed in terms of exciton binding energies and photocurrent transport.