Population inversion between Γ subbands in quantum wells under the conditions of Γ-L intervalley transfer

Abstract

Monte Carlo simulations of electron transport in AlxGa1−xAs/GaAs/InyGa1−yAs double-quantum-well heterostructures in high lateral electric fields are carried out. It is shown that, under the conditions of intervalley Γ-L electron transfer, there exists a population inversion between the first and the second quantum-confinement subbands in the Γ valley. The population inversion appears in the fields exceeding 4 and 5.5 kV/cm at 77 and 300 K, respectively. The gain in a superlattice composed of such quantum wells is estimated to be on the order of 100 cm−1 for radiation with a wavelength of 12.6 µm.