Far-infrared spectroscopy in strained AlSb/InAs/AlSb quantum wells

Abstract

The authors have studied the cyclotron resonance (CR) of 2D electrons in strained InAs single quantum wells, which are grown on either a GaSb or an AlSb buffer layer in order to vary the degree of strain in InAs. For samples with a GaSb buffer layer, the measured CR mass, depending upon the quantum well thickness, varies from 0.0339m0 to 0.0468m0, which is heavier than that of bulk InAs at the conduction band edge, 0.0234m0. This finding is quantitatively explained by the non-parabolicity effect in InAs and the mass renormalization effect originating from the penetration of the electron wavefunction into the barriers. On the other hand, for samples with an AlSb buffer layer, the CR mass, depending upon the carrier concentration, varies from 0.0320m0 to 0.0412m0, and is lighter than that of equal well thickness but with a GaSb buffer. This reduction in mass is accounted for by the stronger misfit strain in InAs when an AlSb buffer layer is used.