Dramatic photoinduction of hole tunneling in double quantum wells with built-in piezoelectric fields

We show that efficient tunneling of holes can be produced in double quantum wells with built-in piezoelectric fields by the photo- screening of that piezoelectric field. Our observation was made at low temperatures by comparing the behavior of ${\mathrm{Ga}}_{0.92}$ ${\mathrm{In}}_{0.08}$As-GaAs strained-layer double quantum wells grown along the (111) and (001) directions and tuning the densities of photoinjected carriers over several decades. Interpretation of the experimental data is made by comparison with Hartree calculations including the space charge effects. In addition to this, we also report the observation of many-body interactions at high photocarrier densities.