OPTICAL PHENOMENA ACCOMPANYING ELECTRON HEATING IN MULTIPLE-QUANTUM WELLS GAAS-ALGAAS BY A LONGITUDINAL ELECTRIC-FIELD

Optical phenomena have been studied in a system of selectively doped n-type quantum wells formed by GaAs-AlGaAs heterojunctions. The absorption spectrum was studied for light of two polarizations at wavelengths near 10 mu m during electron transitions between minibands of the conduction band. A study of the interband spectrum of photoluminescence excitation has made it possible to refine the superlattice parameters. Intensity modulation of the beam from a CO2 laser has been observed. Spontaneous emission of light has also been observed near 10 mu m during heating of 2D electrons by an electric field applied along the quantum-well layers. The modulation is different for light polarized perpendicular and parallel to the layers. An electrooptic effect has been observed during electron heating by a longitudinal electric field. The mechanism for the change in optical absorption accompanying electron heating is discussed. (C) 1995 American Institute of Physics.