High Efficiency Thin Film Superlattice Thermoelectric Cooler Modules Enabled by Low Resistivity Contacts

TL;DR

This paper combines experimental and theoretical methods to understand and develop low-resistivity metal contacts for V-telluride superlattice thermoelectric devices, significantly enhancing cooling performance.

Contribution

It provides a comprehensive approach to designing low-resistivity contacts, including ab initio calculations, experimental fabrication, and characterization, leading to a 100-fold reduction in contact resistivity.

Findings

Achieved a 100-fold reduction in contact resistivity.

Demonstrated improved thermoelectric cooling module performance.

Identified interfacial structures influencing contact resistivity.

Abstract

V-telluride superlattice thin films have shown promising performance for on-chip cooling devices. Recent experimental studies have indicated that device performance is limited by the metal/semiconductor electrical contacts. One challenge in realizing a low resistivity contacts is the absence of fundamental knowledge of the physical and chemical properties of interfaces between metal and V-telluride materials. Here we present a combination of experimental and theoretical efforts to understand, design and harness low resistivity contacts to V-tellurides. Ab initio calculations are used to explore the effects of interfacial structure and chemical compositions on the electrical contacts, and an ab initio based macroscopic model is employed to predict the fundamental limit of contact resistivity as a function of both carrier concentration and temperature. Under the guidance of theoretical studies, we develop an experimental approach to fabricate low resistivity metal contacts to V-telluride thin film superlattices, achieving a 100-fold reduction compared to previous work. Interfacial characterization and analysis using both scanning transmission electron microscopy and energy-dispersive x-ray spectroscopy show the unusual interfacial morphology and the potential for further improvement in contact resistivity. Finally, we harness the improved contacts to realize an improved high-performance thermoelectric cooling module.