Quasi-two-dimensionality in narrow channel field-effect transistors-an interpolation model

The operation of a special GaAs-MESFET (metal-semiconductor field-effect transistor), originally proposed by M. Pepper (1977) for studies of low dimensional transport at low temperatures, is analysed in terms of a modified oscillator model designed for the quantum limit (narrow channels, low temperatures). The relation between the electron concentration and the gate voltage is calculated in the quantum limit and compared with the results of the bare oscillator model and the abrupt depletion model. The sublevels and the depopulation of sub-bands in the case of an applied magnetic field are calculated and compared with experiments. The major advantage of this model is the simple analytical structure of the measurable quantities.