High pressure studies of resonant tunnelling and superlattice phenomena

Abstract

Hydrostatic pressure is used to investigate two types of device based upon the n-type GaAs/(AlGa)As material system: an asymmetric double barrier resonant tunnelling device and a device incorporating two superlattices separated by a single barrier. In the double barrier structure, the pressure-induced increase in Gamma -X tunnelling and scattering reduces the build-up of electronic space charge in the GaAs quantum well. This allows one to study the transition from intrinsic bistability to ordinary negative differential conductivity in I(V). In the superlattice/barrier/superlattice structure the authors have evidence for a pressure-induced decrease in the free-electron density of the heavily doped n+ contact regions due to DX centres.