Using polymer electrolyte gates to set-and-freeze threshold voltage and local potential in nanowire-based devices and thermoelectrics

TL;DR

This paper demonstrates how polymer electrolyte gates can precisely set and freeze local potentials in nanowire devices at low temperatures, enhancing control for thermoelectric applications.

Contribution

It introduces a method to 'freeze in' ionic charge environments around nanowires using polymer electrolytes, enabling stable local gating at cryogenic temperatures.

Findings

Polymer electrolyte gates can set threshold voltages below 200 K.

Local disorder potentials can be characterized by conductance and thermovoltage measurements.

Polymer electrolyte gates are compatible with nanowire thermoelectrics and have low thermal conductivity.

Abstract

We use the strongly temperature-dependent ionic mobility in polymer electrolytes to 'freeze in' specific ionic charge environments around a nanowire using a local wrap-gate geometry. This enables us to set both the threshold voltage for a conventional doped substrate gate and the local disorder potential at temperatures below 200 Kelvin, which we characterize in detail by combining conductance and thermovoltage measurements with modeling. Our results demonstrate that local polymer electrolyte gates are compatible with nanowire thermoelectrics, where they offer the advantage of a very low thermal conductivity, and hold great potential towards setting the optimal operating point for solid-state cooling applications.