GaAs-Based Single Electron Transistors and Logic Inverters Utilizing Schottky Wrap-Gate Controlled Quantum Wires and Dots

Abstract

GaAs-based single electron transistors (SETs) and their logic inverters were successfully designed and fabricated using a Schottky wrap-gate (WPG) quantum wire and dot formation technology. Three-gate WPG SETs, which have two tunnel barrier gates and a center gate for a quantum dot-potential control, showed voltage gains larger than unity due to tight dot-potential control of the center WPG. The conductance peak position of the SET could be systematically controlled by changing the tunnel-barrier-control WPG voltages. A resistive-load single electron inverter utilizing a 3-gate WPG SET as a driver and a WPG quantum wire transistor as an active load was fabricated and it showed a proper inverter operation at 1.6 K and realized a logic transfer gain of larger than unity (1.3) for the first time in III-V semiconductor-based SET inverters. A III-V semiconductor-based complimentary inverter utilizing two 3-gate WPG SETs was also successfully fabricated for the first time and the inverter operation was also confirmed at 1.7 K.