Electric-field-dependent photoconductivity in GaInAs-InP quantum wells

Publisher Website
Google Scholar
Abstract
We report a study of the effects of an electric field on the excitonic, band-to-band photoconductivity spectra of a Ga0.47In0.53As-InP quantum well structure. In a sample with five wells of widths 10–110 Å we show that for carrier motion normal to the quantum well layers a photoconductivity signal is only observed from those wells which are in a region of nonzero electric field. The spectral line shapes of the transitions in the narrowest two wells show strong variations with field, which we attribute to exciton dissociation at high field, and possibly exciton screening by free carriers trapped in the wells at low fields. The results are compared with photoconductivity spectra of the same structure, but for carrier motion in the plane of the layers. The latter geometry is found to reflect more accurately the sample absorption.