Electronic-structure of Si delta-doped GaAs in an electric-field

Abstract

The electron dynamics and the density of states of both single and periodic Si delta-doped GaAs subject to an applied electric field are studied theoretically. The space charge potential due to delta-doping is obtained by means of the semiclassical Thomas-Fermi model. Analysing the change in the density of states introduced by the delta-doping plus the electric field, we observe a set of sharp peaks, corresponding to field-induced localized states, and subsidiary peaks associated with more extended states. Furthermore, we use the inverse participation ratio to evaluate the spatial extent of electron wavefunctions. The number of sharp peaks equals the number of delta-doped layers. In the case of periodically delta-doped samples, the sharp peaks are equally spaced and give rise to Stark ladder resonances.