Giant room-temperature terahertz photothermoelectric response mediated by hot carriers at the metal-semimetal interfaces.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40367167.
- Also identified by DOI 10.1126/sciadv.adv0768 and PMC identifier 12077501.
- Licence recorded as CC BY-NC.
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Abstract
The hot-carrier photothermoelectric (PTE) effect in two-dimensional materials can be used to develop room-temperature, fast, and sensitive detectors for microwave, terahertz, and far-infrared radiations. Here, we present a van der Waals semimetal PtSe<sub>2</sub> terahertz detector and find a giant terahertz PTE response mediated by hot carriers at the metal-PtSe<sub>2</sub> interfaces. The detector demonstrates an excellent zero-bias responsivity of 0.62 ampere per watt (A/W), a low-noise equivalent power of 19.6 picowatt per square root of hertz (pW/Hz<sup>1/2</sup>), and a fast response time of 4.5 nanosecond (ns) at 0.1 terahertz (THz). The metal doping effect and asymmetric terahertz heating play vital roles in the hot-carrier PTE response at the metal-semimetal interfaces. Moreover, scanning photocurrent mapping shows that the short-wave zero-bias photoresponse is closely localized to the metal-semimetal interfaces, further revealing the metal doping effect. The bias-dependent photocurrent indicates that the short-wave photoresponse still originates from the PTE effect and the photovoltaic response is negligible. Our results provide important guidance for developing high performance semimetal detectors.