Fabrication and Characterization of GaAs Single Electron Devices Having Single and Multiple Dots Based on Schottky In-Plane-Gate and Wrap-Gate Control of Two-Dimensional Electron Gas

Abstract

Single-dot and multiple (2, 3, 18, and 37)-dot single electron transistors (SETs) based on the control of a two-dimensional electron gas (2DEG) with a recently proposed Schottky in-plane gate (IPG) and a newly introduced Schottky wrap gate (WPG) were successfully fabricated on AlGaAs/GaAs wafers using electron beam (EB) lithography and their transport properties were investigated. Each of the fabricated SETs showed Coulomb blockade-like conductance oscillation. In single-dot SETs, a strong correlation was found between the device dimensions and the temperature limit of the conductance oscillation. Conductance oscillation characteristics of multiple-dot SETs were complicated, and were not explained by the classical Coulomb blockade theory. Based on a simplified theoretical analysis using computer simulation, it was shown that quantized energy due to electron confinement and dot-coupling can dominate the charging effect in the fabricated SETs.