Gamma- and X-band contributions to nonresonant tunneling in GaAs/Al0.35Ga0.65As double quantum wells.

Time-resolved photoluminescence in the picosecond rgime is performed on an asymmetric GaAs/Al0.356G0.65As double quantum well structure with a barrier thickness of 6 nm to obtain the Gamma - and Chi-point barrier contributions to nonresonant tunneling. Application of hydrostatic pressure up to 37 kbar at 5 K reveals that tunneling via virtual Chi states is at least 800 times less efficient than via virtual Gamma states. Above 24.5 kbar an extremely fast scattering of electrons out of the n = 1 quantized level of the narrower quantum well is observed.