Electroluminescence investigations of electron and hole resonant tunneling in p-i-n double-barrier structures

The electroluminescence and current-voltage characteristics of a p-i-n double-barrier structure based on GaAs/AlAs are investigated. Electroluminescence lines due to carrier recombination in the GaAs contact layers and in the quantum well are observed. The bias dependence of the intensity of these lines exhibits the pronounced peaks that are also seen in the I(V) characteristics, which are due to electron and hole resonant tunneling. The quantum-well emission lines correspond to recombination of holes in the two lowest-energy valence subbands (LH1 and HH1). Their relative intensities indicate that the hole population in these subbands is inverted over a wide range of bias. A rapid cooling of the holes is observed when the electron density in the quantum well is high.