Electronic transport through very short and narrow channels constricted in GaAs by highly resistive Ga-implanted regions

Abstract

Very short and narrow channels are fabricated by use of focused-ion-beam implantation into a ${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As/GaAs modulation-doped epilayer. The channels are constricted by highly resistive Ga-implanted regions. The electron transport experiments exhibited a prominent quantization of conductance characteristics, which is peculiar to ballistic transport through one-dimensional subbands. These quantized conductance characteristics are observed until the temperature is raised to approximately 10 K. In addition to the quantized conductance, large conductance fluctuations are observed at low temperatures.