Large and tunable photothermoelectric effect in single-layer MoS2.

Buscema, Michele; Barkelid, Maria; Zwiller, Val; van der Zant, Herre S J; Steele, Gary A; Castellanos-Gomez, Andres · Nano Lett · 2013

basic_science · Level V

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Abstract

We study the photoresponse of single-layer MoS(2) field-effect transistors by scanning photocurrent microscopy. We find that, unlike in many other semiconductors, the photocurrent generation in single-layer MoS(2) is dominated by the photothermoelectric effect and not by the separation of photoexcited electron-hole pairs across the Schottky barriers at the MoS(2)/electrode interfaces. We observe a large value for the Seebeck coefficient for single-layer MoS(2) that by an external electric field can be tuned between -4 × 10(2) and -1 × 10(5) μV K(-1). This large and tunable Seebeck coefficient of the single-layer MoS(2) paves the way to new applications of this material such as on-chip thermopower generation and waste thermal energy harvesting.