Electron conduction in an atomic-layer-doped gaas plane

Electronic transport characteristics in Si atomic-layer-doped GaAs are investigated using Hall measurements. In the uniformly Si-doped GaAs crystals, the carrier concentration varies very little throughout the whole temperature range, while the atomic-layer-doped GaAs layer exhibits a strong temperature-dependent electron concentration with a minimum value around 100 K. The temperature dependence of the sheet resistance of the Si atomic-layer-doped GaAs is quite different from that of the uniformly Si-doped GaAs. The observed characteristics are interpreted by considering parallel conduction in the Si atomic-layer-doped GaAs. We propose a hypothetical model that the electrons are confined by a local potential well structure due to the random distribution of Si atoms in the atomic-layer-doped plane. Using this model, we also discuss the discrepancy reported so far between the doped layer thickness evaluated from magnetoresistance measurements and that from C-V profiling measurements.