Tunneling process in AlAs/GaAs double quantum wells studied by photoluminescence

Abstract

The tunneling process of photogenerated carriers in AlAs/GaAs double quantum well structures in which two wells have different widths (60 and 80 Å) was studied by steady-state and time-resolved photoluminescence spectra. The tunneling process was found to play an important role for a barrier thickness narrower than about 40 Å. The tunneling rate was determined as 2×1010 s−1 for a 30-Å barrier. The quantum-mechanical penetration depth of the wave function into an AlAs barrier was estimated as 6 Å from the barrier width dependence of luminescence intensity ratio between the two wells. The tunneling rate and penetration depth are consistent with a simple envelope function approximation with no Γ-X mixing.