Luminescence in p–i–n Structures with Compensated Quantum Wells

Abstract

Photo- and electroluminescence in p–i–n structures with compensated GaAs/AlGaAs quantum wells have been studied. Two structures with different doping profiles were studied: with spatial separation of donors and acceptors (donors are localized in quantum wells, while acceptors are localized in barriers) and without it (both donors and acceptors are localized in quantum wells). The studies were carried out in the near-IR range at helium temperatures. Luminescence lines due to electron transitions from donor states to the first heavy-hole subband (D–hh1) and from the first electron subband to acceptor states (e1–A) have been identified. At large electric currents, the near-IR lasing due to these transitions was observed in the electroluminescence spectra. It has been found that the integrated lasing intensity related to the D–hh1 transitions in the structure without a spatial separation of donors and acceptors was three times higher than in the structure with the spatial separation. It is these transitions that ensure effective depletion of donor levels, which is important for the donor-assisted terahertz emission at e1–D electron transitions. The results of the work can be used in the development of electrically pumped terahertz emitters.