Auger recombination in semiconductor quantum wells in a magnetic field

Abstract

Auger process involving two electrons from the conduction band and a heavy hole from the valence band in semiconductor heterostructures with quantum wells is investigated for the case of a magnetic field applied normal to heteroboundaries. It is shown that there exist three different mechanisms of Auger recombination, associated with ͑I͒ electron scattering at interface with transition into the continuous spectrum, ͑II͒ short-range Coulomb interaction in the quantum well with transition into the continuous spectrum, and ͑III͒ resonance transition into the discrete spectrum. All these processes are thresholdless. The Auger recombination coefficients analytically calculated for the processes I, II, and III show different dependencies on temperature, magnetic field, and quantum well parameters. In the limit of an infinitely wide quantum well, processes I and II merge to form a bulk threshold Auger process, while process III remains thresholdless resonance one. In the limit of infinitely weak magnetic field, process I remains thresholdless, process II becomes a quasithreshold process ͑i.e., its threshold energy slightly depends on temperature͒, and process III transforms into a nonresonance process with a threshold. The results obtained are new and have no analogies in the literature.

Terahertz photoconductivity of a two‐dimensional electron gas in HgCdTe/HgTe quantum wells

“…Emitting acoustical phonons 9 which is dominated in two‐dimensional systems becomes ineffective at magnetic fields 10. The recombination lifetime defined in our experiments as tens and hundreds of nanoseconds can be attributed either to the radiating carrier recombination between Landau levels or to Auger processes 11. Both mechanisms seem to contribute equally but their detailed analysis is out of the scope of this paper.…”