Eur. Phys. J. B 47, 305-314 (2005)
https://doi.org/10.1140/epjb/e2005-00326-9

Contactless gating, surface charging and illumination effects in a buried Al_0.24Ga_0.76As/GaAs quantum well structure

¹ Department of Physics, University of California Riverside, Riverside CA 92521, USA
² ENEA, Via Don Fiammelli 2, 40129 Bologna, Italy
³ Bell Laboratories, Lucent Technologies, Murray Hill NJ 07974, USA
⁴ Los Alamos National Laboratory, Los Alamos, NM 87545, USA

Corresponding author: ^a biasini@physics.ucr.edu

Received: 29 April 2005
Revised: 11 July 2005
Published online: 11 October 2005

Abstract

The conductivity of an Al_0.24Ga_0.76As/GaAs quantum well was studied as a function of the surface charge generated by electron bombardment of the sample in the absence of an externally applied surface electric field. Under a suitable rate of electron irradiation, it was possible to completely shut off the conductive channel, implying a surface density . Light illumination quenches the increase of the resistivity, apparently due to photoemission from the metastable surface states. Upon turning off the electron bombardment the surface charge on adsorbed layers of xenon and water at 8 K decays in room temperature darkness with a lifetime s. The average charging efficiency, is . Surface charging is shown to be an effective method for contactless gating of field effect devices.