Temperature dependence of electron transfer in coupled quantum wells

We report on the temperature dependence of electron transfer between coupled quantum wells in a voltage tunable two-color quantum-well infrared photodetector (QWIP). The detection peak of this QWIP switches from 7.1 mum under positive bias to 8.6 mum under negative bias for temperatures Tless than or equal to40 K. For Tgreater than or equal to40 K, the 7.1 mum peak is present under both bias polarities and increases significantly with T while the 8.6 mum peak decreases correspondingly. We determine the temperature dependence of electron densities in the two QWs from the detector absorption spectra that are deduced using corrugated QWIPs and find that electron transfer is efficient only when thermionic emission is not significant. (C) 2003 American Institute of Physics.