Fabrication and Shot Noise Characteristics of Ultra-Small Split-Gate GaAs Quantum Dots

Abstract

We demonstrate the fabrication and the electrical characterization of lithographically-defined ultra-small lateral quantum dots based on a GaAs/AlGaAs heterostructure composed of tunable split metal gates. We evaluated two quantum dots have charging energies of 4.31 and 4.99 meV, respectively, from a measurement of the Coulomb diamond plot obtained from the 2-dimensional differential conductance via gate and source-drain biases. These values axe some of the largest energy scales ever reported for a lateral split-gate type single-electron device. We also measured the shot noise from a quantum dot by using a low-frequency noise measurement technique. Elastic cotunneling, inelastic cotunneling and sequential tunneling were analyzed using conductance and shot noise measurements.