Piezoelectric effects in double barrier resonant tunneling structures

摘要

It is shown that piezoelectric effects can give rise to internal electric fields that modify the conventional current vs. voltage characteristics of III-V semiconductor double barrier resonant tunneling devices, if suitable stresses are applied. We measured current vs. voltage characteristics of symmetric, (001)-oriented AlAs/GaAs/AlAs double barrier structures as a function of external stress. Uniaxial stress was applied parallel to the (110), the (110), and the (001) directions. In order to understand the experimental results we calculated the current vs. voltage characteristics of resonant tunneling structures under uniaxial stress, including pressure effects on the band alignment and the effects associated with the piezoelectric nature of the constituent materials. Stresses along the (110) or (110) directions give rise to polarization charges at the interfaces, due to differences in the piezoelectric constants of the materials. The resulting internal electric fields are found to modulate the I-V characteristics, in good agreement with our experimental data.