Drain voltage induced barrier increasing of quantum-wire transistors

In-plane quantum-wire transistors based on a modulation-doped GaAs/AlGaAs heterostructure are studied in the threshold regime. It is found that the threshold voltage V_T of a quantum wire transistor depends on the applied bias voltage in a parabolic way. In particular, V_T increases in the strong nonlinear transport regime with increasing bias voltage, which is in contrast to the drain voltage induced barrier lowering observed for submicron transistors. The increase of V_T by a barrier increase along the channel with increasing bias voltage due to a self-depletion is explained.