Single-hole transistor in p-type GaAs/AlGaAs heterostructures

TL;DR

This paper reports the fabrication and characterization of a single-hole transistor in p-type GaAs/AlGaAs heterostructures, demonstrating Coulomb blockade and multi-level transport at low temperatures.

Contribution

It introduces a novel single-hole transistor in p-type GaAs/AlGaAs with detailed Coulomb blockade analysis and transport regime identification.

Findings

Observation of Coulomb blockade resonances at 300 mK

Charging energy of approximately 1.5 meV

Evidence of multi-level transport regime

Abstract

A single-hole transistor is patterned in a p-type, C-doped GaAs/AlGaAs heterostructure by AFM oxidation lithography. Clear Coulomb blockade resonances have been observed at T=300 mK. A charging energy of ~ 1.5 meV is extracted from Coulomb diamond measurements, in agreement with the lithographic dimensions of the dot. The absence of excited states in Coulomb diamond measurements, as well as the temperature dependence of Coulomb peak heights indicate that the dot is in the multi-level transport regime. Fluctuations in peak spacings larger than the estimated mean single-particle level spacing are observed.