Phase-Engineered PtSe2 -Layered Films by a Plasma-Assisted Selenization Process toward All PtSe2 -Based Field Effect Transistor to Highly Sensitive, Flexible, and Wide-Spectrum Photoresponse Photodetectors

Teng-Yu Su; Henry Medina; Yu-Ze Chen; Sheng-Wen Wang; Shao-Shin Lee; Yu-Chuan Shih; Chia-Wei Chen; Hao-Chung Kuo; Feng-Chuan Chuang; Yu-Lun Chueh

doi:10.1002/smll.201800032

Phase-Engineered PtSe₂ -Layered Films by a Plasma-Assisted Selenization Process toward All PtSe₂ -Based Field Effect Transistor to Highly Sensitive, Flexible, and Wide-Spectrum Photoresponse Photodetectors

Small. 2018 May;14(19):e1800032. doi: 10.1002/smll.201800032. Epub 2018 Apr 10.

Authors

Affiliations

¹ Department of Material Science and Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan.
² Institute of Materials Research and Engineering (IMRE), A*STAR, 2 Fusionopolis Way, Innovis, Singapore, 138634, Singapore.
³ Department of Photonics & Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan.
⁴ Department of Physics, National Sun Yat-Sen University, Kaohsiung, 80424, Taiwan.

PMID: 29635730
DOI: 10.1002/smll.201800032

Abstract

The formation of PtSe₂ -layered films is reported in a large area by the direct plasma-assisted selenization of Pt films at a low temperature, where temperatures, as low as 100 °C at the applied plasma power of 400 W can be achieved. As the thickness of the Pt film exceeds 5 nm, the PtSe₂ -layered film (five monolayers) exhibits a metallic behavior. A clear p-type semiconducting behavior of the PtSe₂ -layered film (≈trilayers) is observed with the average field effective mobility of 0.7 cm² V^-1 s^-1 from back-gated transistor measurements as the thickness of the Pt film reaches below 2.5 nm. A full PtSe₂ field effect transistor is demonstrated where the thinner PtSe₂ , exhibiting a semiconducting behavior, is used as the channel material, and the thicker PtSe₂ , exhibiting a metallic behavior, is used as an electrode, yielding an ohmic contact. Furthermore, photodetectors using a few PtSe₂ -layered films as an adsorption layer synthesized at the low temperature on a flexible substrate exhibit a wide range of absorption and photoresponse with the highest photocurrent of 9 µA under the laser wavelength of 408 nm. In addition, the device can maintain a high photoresponse under a large bending stress and 1000 bending cycles.

Keywords: field effect transistors; low-temperature synthesis; metallic to semiconducting; plasma-assisted; platinum diselenide; transition metal dichalcogenide.