Abstract
Temperature-dependent Hall-effect measurements are reported and analyzed in detail for -type of composition grown by molecular-beam epitaxy and highly doped with Si ( ). A quantitative analysis using Fermi-Dirac statistics reveals for the composition range the presence of a hydrogenlike shallow Si donor which interacts with the valley and a deep Si donor related to the valley. In contrast to previous results, the thermal activation energy of the deep donor, determined to be meV, does not change significantly with alloy composition. Only the ratio of shallow-to deep-donor concentration depends on composition. For , neither deep-donor nor persistent photoconductivity exists in -type . For , however, the deep-donor concentration increases with while simultaneously the shallow-donor concentration decreases. The proposed interaction of the deep donor with the valley helps in understanding the persistent photoconductivity found in -type with .
- Received 21 May 1984
DOI:https://doi.org/10.1103/PhysRevB.30.7021
©1984 American Physical Society