Lateral confinement of carriers in ultrathin semiconductor quantum wells

Abstract

We investigate theoretically the effects of one-dimensional lateral confinement on the electronic states in strained ultrathin quantum wells (QWs). We studied two monolayer (ML) thick InAs/InP (001) QWs containing 3 ML thick one-dimensional (wire-like) InAs islands from 2 to 45 ML wide, oriented along the 〈010〉 and 〈110〉 directions. Localized (wire) and extended (QW) states are found in the energy spectra of the structures. The wire localization leads to a band-gap reduction and to an increase of the heavy hole–light hole splitting. Coupling between extended and localized states is observed at certain wire widths, indicating that these structures cannot be regarded simply as consisting of independent regions with different QW widths.