Spatially Resolved Thermoelectric Effects in Operando Semiconductor-Metal Nanowire Heterostructures

TL;DR

This study uses scanning thermal microscopy to analyze the thermoelectric properties of nanoscale germanium-aluminium heterostructures, enabling detailed temperature and thermoelectric measurements at the nanoscale.

Contribution

It introduces a method to extract thermal and thermoelectric properties from single measurements of self-heated nanowires with atomically sharp interfaces.

Findings

Quantitative temperature distribution measurements around nanostructures.

Extraction of thermal conductivity and boundary resistance from single measurements.

Demonstration of nanoscale thermoelectric characterization capabilities.

Abstract

The thermoelectric properties of a nanoscale germanium segment connected by aluminium nanowires are studied using scanning thermal microscopy. The germanium segment of 168\,nm length features atomically sharp interfaces to the aluminium wires and is surrounded by an Al$_2$O$_3$ shell. The temperature distribution along the self-heated nanowire is measured as a function of the applied electrical current, for both Joule and Peltier effects. An analysis is developed that is able to extract the thermal and thermoelectric properties including thermal conductivity, the thermal boundary resistance to the substrate and the Peltier coefficient from a single measurement. Our investigations demonstrate the potential of quantitative measurements of temperature around self-heated devices and structures down to the scattering length of heat carriers.