Quantized conductance and its effects on non-linear current-voltage characteristics at 80 K in mesa-etched InAs/AlGaSb quantum wires with split-gate

Abstract

We report electrical characteristics of InAs ( AlGa) Sb quantum wire devices based on deep mesa-etched structures with split gate. Quantized current and conductance has been observed at around 80 K for the first time. Current quantization analysis revealed that the quantized conductance showed constant value with the drain voltages up to ≈180 mV suggesting that the Landauer's formula in one-dimensional electron systems in finite voltages holds up to ≈180 mV. The 3650 Å-wide, 3625 Å long InAs quantum wire showed non-linear I- V characteristics with fixed gate voltage. The drain current dependence on matrix of gate and drain voltages revealed that the current increase at high drain voltages is caused by the so called drain-induced-barrier-lowering: sublevels at the point contact are actually lowered by the application of high drain voltage which has a same effect as positive gate voltage application. Overall drain current saturation tendency is caused presumably by the saturation velocity effect in the high field region between the point contact and rest of the wire under high drain voltage.