Transport properties of GaAs layers grown by molecular beam epitaxy at low temperature and the effects of annealing

The effects of growth temperature and subsequent annealing temperatures on the electrical properties of the low temperature (LT) grown GaAs have been investigated. It was found that the resistivity of the as‐grown LT‐GaAs layer increased with increasing growth temperature, but was accompanied by a reduction of breakdown voltage over the same temperature range. Thermal annealing of the samples caused the resistivity to rise exponentially with increasing annealing temperature TA, giving an activation energy of EA=2.1 eV. The transport of the LT‐GaAs layers grown at Tg≤250 °C was found to be dominated by hopping conduction in the entire measurement temperature range (100–300 K), but following annealing at TA≳500 °C, the resistivity‐temperature dependence gave an activation energy of ∼0.7 eV. The breakdown voltage VBD, for as‐grown LT‐GaAs was enhanced on lowering the measurement temperature, but conversely, decreased over the same temperature range following annealing at TA≳500 °C. The hopping conduction bet...