Midinfrared luminescence from InAs quantum dots in unipolar devices

Midinfrared light has been obtained from InAs quantum dots (QDs) in unipolar semiconductor devices with moderate current densities at low temperatures (77 K). The luminescence signals are broad, extending from the 70 meV cutoff of the HgCdTe detector to 200 meV, however they exhibit a peak at about 150 meV and are clearly distinct from thermal radiation. The QDs are contained within a resonant tunneling structure which includes a superlattice (AlGaAs/GaAs) electron energy filter and are grown with all n-type material by molecular-beam epitaxy. Electroluminescence and photoluminescence experiments have been used to examine the transitions responsible for the midinfrared emission.