Resonant and nonresonant tunneling in GaAs/Al xGa 1− xAs asymmetric double quantum wells

Abstract

Electron and hole tunneling transfer processes in asymmetric double quantum well structures are investigated by time-resolved picosecond photoluminescence. Change from nonresonant to resonant tunneling is achieved with a perpendicular electric field. Electron transfer times become considerably faster in the resonant regime, but the transfer times still decrease strongly with barrier thickness. The resonances shift to higher bias values for increasing excitation densities. Nonresonant hole tunneling with fast transfer times occurs without the contributions of optical phonons. Resonances in the hole tunneling transfer times seem to result from mixing effects between heavy and light holes in adjacent wells.