Transport properties of closely separated two-dimensional electron gases in a channel-doped back gated high electron mobility transistor

We have investigated electron transport in two, closely separated, two-dimensional electron gases in a wide GaAs quantum well controlled both by front and back gates. The electron mobility in the back channel was considerably reduced by impurity doping. Magnetotransport measurements suggest the existence of a low mobility state associated with a high mobility front gas state. The results have a bearing on the proposed velocity modulation transistor, as the existence of two electron channels localized at their respective interfaces, without mutual interaction, can be difficult to achieve.