Abstract
The variation of the potential of a quantum well is similar to that of a deep trap. In that respect a quantum well can capture and emit carriers in much the same way as a trap. The thermal emission energy from a quantum well is closely related to the appropriate band offset. With that in mind, we have carried out deep-level transient spectroscopy measurements on Schottky-barrier diodes containing one or more pseudomorphic As/As (0<x≤0.18) quantum wells. The objective was to estimate the conduction-band offset, Δ, as a function of x and the resulting strain. From detailed balance between emission and capture, an Arrhenius-type expression was derived to analyze the transient emission data. It is seen that the percentage band offset Δ/Δ varies from 62% for x=0.07 to 70% at x=0.18. Furthermore, a linear interpolation of the data leads to Δ/Δ=58% at x=0, which is close to the widely accepted value. Our results support recent theoretical calculations from which a monotonic increase in Δ with strain in this heterostructure system is predicted.
- Received 27 February 1989
DOI:https://doi.org/10.1103/PhysRevB.40.1058
©1989 American Physical Society