Abstract
Molecular-beam-epitaxial GaAs grown at very low temperatures (∼200 °C) exhibits anomalous Hall-effect properties. Here we show conclusively that the room-temperature conduction is due to activated (nearest-neighbor) hopping in a deep defect band of concentration 3× , and energy -0.75 eV, along with conduction due to free carriers thermally excited from this band. At low measurement temperatures, variable-range hopping [σ∝exp(-/T] prevails. The conduction-band mobility can be well explained by neutral-deep-donor scattering in parallel with lattice scattering.
- Received 26 April 1990
DOI:https://doi.org/10.1103/PhysRevB.42.3578
©1990 American Physical Society