Thermopower-enhanced efficiency of Si/SiGe ballistic rectifiers

TL;DR

This paper investigates Si/SiGe ballistic rectifiers and demonstrates how gate voltage manipulation can significantly enhance transfer resistance through thermopower effects, reaching up to 470 Ohm near threshold.

Contribution

It introduces a novel approach to improve ballistic rectifier efficiency by exploiting thermopower contributions influenced by gate configurations.

Findings

Maximum transfer resistance of 470 Ohm achieved near threshold.

Thermopower effects can either cancel or reinforce the ballistic signal.

Gate voltage controls thermopower contributions and rectifier performance.

Abstract

Injection-type ballistic rectifiers on Si/SiGe are studied with respect to the influence of gate voltage on the transfer resistance RT (output voltage divided by input current) for different positions of a local gate electrode. The rectifiers are trifurcated quantum wires with straight voltage stem and oblique current-injecting leads. Depending on the gate configuration, thermopower contributions arise from nearly-pinched stem regions which either cancel each other or impose upon the ballistic signal with same or opposite polarity. At best, this enhances RT to a maximum value of 470 Ohm close to threshold voltage.