Optical phonon emission in GaAs/AlAs and GaAs/Al0.7Ga0.3As multiple quantum well structures

We have performed Raman scattering measurements and hot electron-neutral ac ceptor (hot(e, Angstrom)) luminescence experiments on Be-doped GaAs/AlAs an d GaAs/Al0.7Ga0.3As multiple quantum well structures, with fixed well width of 50 Angstrom and barrier thickness of 5, 25, 50,120 Angstrom, to determi ne the optical phonon energy emitted by the hot electrons excited in the qu antum wells. It was shown that the relaxation of electrons in the GaAs laye r is dominated by the AlAs-like optical phonon emission for samples with la rger barriers, but by GaAs optical phonons for smaller barriers. (C) 2001 E lsevier Science B.V. All rights reserved.