Normal-incident intersubband photocurrent spectroscopy on InAs/GaAs quantum dots

Abstract

We report on intersubband photocurrent spectroscopy of self-assembled InAs/GaAs quantum dots (QDs) both in normal incidence and in multipass waveguide geometry. The bound-to-continuum transition energy in the conduction band lies in the 200–500 meV spectral range. Polarization dependent photocurrent spectroscopy shows that the intersubband transitions in the InAs-QDs are nearly independent of the polarization of the incoming radiation.