title: Surface band-gap narrowing in quantized electron accumulation layers.
abstract: An energy gap between the valence and the conduction band is the defining property of a semiconductor, and the gap size plays a crucial role in the design of semiconductor devices. We show that the presence of a two-dimensional electron gas near to the surface of a semiconductor can significantly alter the size of its band gap through many-body effects caused by its high electron density, resulting in a surface band gap that is much smaller than that in the bulk. Apart from reconciling a number of disparate previous experimental findings, the results suggest an entirely new route to spatially inhomogeneous band-gap engineering.
authors.affiliation: Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom. philip.d.c.king@physics.org
authors.forename: P D C
authors.initials: PD
authors.lastname: King
authors.forename: T D
authors.initials: TD
authors.lastname: Veal
authors.forename: C F
authors.initials: CF
authors.lastname: McConville
authors.forename: J
authors.initials: J
authors.lastname: Zúñiga-Pérez
authors.forename: V
authors.initials: V
authors.lastname: Muñoz-Sanjosé
authors.forename: M
authors.initials: M
authors.lastname: Hopkinson
authors.forename: E D L
authors.initials: ED
authors.lastname: Rienks
authors.forename: M Fuglsang
authors.initials: MF
authors.lastname: Jensen
authors.forename: Ph
authors.initials: P
authors.lastname: Hofmann