Lateral intersubband photocurrent spectroscopy on InAs/GaAs quantum dots

We report on lateral intersubband photocurrent spectroscopy on self-assembled InAs/GaAs quantum dots in normal incidence. The in-plane polarized intersubband transition between the first exited states and wetting layer in the conduction band is peaked at 180 meV with a spectral linewidth of 20 meV. In-plane polarization dependent measurements show that the energy separation between the (100) and (010) states caused by lateral confinement is about 3.5 meV. A comparison of photoluminescence and vertical and lateral photocurrent experiments leads to a consistent picture of the energy levels in the conduction and valence band.