AlGaAs/GaAs single electron transistors fabricated without modulation doping

TL;DR

This paper reports the fabrication of AlGaAs/GaAs single electron transistors without modulation doping, demonstrating stable Coulomb blockade oscillations and quantum state resolution, advancing quantum dot device technology.

Contribution

It introduces a novel fabrication method for quantum dot transistors without modulation doping, enabling clear Coulomb blockade behavior and excited state transport detection.

Findings

Stable Coulomb blockade oscillations observed

Charging energy directly measured from bias spectroscopy

Quantum states in the dot can be resolved

Abstract

We have fabricated quantum dot single electron transistors, based on AlGaAs/GaAs heterojunctions without modulation doping, which exhibit clear and stable Coulomb blockade oscillations. The temperature dependence of the Coulomb blockade peak lineshape is well described by standard Coulomb blockade theory in the quantum regime. Bias spectroscopy measurements have allowed us to directly extract the charging energy, and showed clear evidence of excited state transport, confirming that individual quantum states in the dot can be resolved.