Electric field effect on the spatially separated electron-hole recombination in an Si/Si1-xGex resonant tunneling heterostructure

摘要

A theoretical analysis, using a self-consistent Schrodinger-Poisson solver, is made to calculate electric field-dependent interband transitions in an Si/Si1-xGex resonant tunneling heterostructure. Two peculiar features are revealed: (i) electron-hole transitions in the collector accumulation layer exhibit a red shift in energy emission and a decreasing oscillator strength as the electric field increases, (ii) interband electron transitions in the emitter accumulation sheet undergo an increase in the oscillator strength and a blue Stark shift with increased electric field. The latter property can be explained as being due to enhanced overlap between the spatially separated electron and hole gases. Resonant tunneling through the double barrier is probably at the origin of the increased oscillator strength. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 20]