Single-material MoS$_{2}$ thermoelectric junction enabled by substrate engineering

TL;DR

This paper demonstrates that substrate engineering can create thermoelectric junctions in ultra-thin MoS2 films, enabling the development of compact thermoelectric power generators without complex doping processes.

Contribution

It introduces a novel substrate engineering approach to form thermoelectric junctions in 2D materials, bypassing traditional doping methods.

Findings

Thermoelectric junctions form across substrate-engineered regions.

Gating effects from interfacial charges influence thermoelectric properties.

Substrate engineering offers a new route for thin-film thermoelectric devices.

Abstract

To realize a thermoelectric power generator, typically a junction between two materials with different Seebeck coefficient needs to be fabricated. Such difference in Seebeck coefficients can be induced by doping, which renders difficult when working with two-dimensional (2d) materials. Here, we employ substrate effects to form a thermoelectric junction in ultra-thin few-layer MoS2 films. We investigated the junctions with a combination of scanning photocurrent microscopy and scanning thermal microscopy. This allows us to reveal that thermoelectric junctions form across the substrate-engineered parts. We attribute this to a gating effect induced by interfacial charges in combination with alterations in the electron-phonon scattering mechanisms. This work demonstrates that substrate engineering is a promising strategy to develop future compact thin-film thermoelectric power generators.