Single-material MoS2 thermoelectric junction enabled by substrate engineering
Mohammadali Razeghi, Jean Spièce, Oğuzhan Oğuz, Doruk Pehlivanoğlu, Yubin Huang, Ali Sheraz, Uğur Başçı, Phillip S. Dobson, Jonathan Weaver, Pascal Gehring, T. Serkan Kasırga
Abstract
Abstract To realize a thermoelectric power generator, typically, a junction between two materials with different Seebeck coefficients needs to be fabricated. Such differences in Seebeck coefficients can be induced by doping, which renders it difficult when working with two-dimensional (2d) materials. However, doping is not the only way to modulate the Seebeck coefficient of a 2d material. Substrate-altered electron–phonon scattering mechanisms can also be used to this end. Here, we employ the substrate effects to form a thermoelectric junction in ultrathin, few-layer MoS 2 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 for developing future compact thin-film thermoelectric power generators.