Optically Controlling Broadband Terahertz Modulator Based on Layer-Dependent PtSe2 Nanofilms

Hong Su; Zesong Zheng; Zhisheng Yu; Shiping Feng; Huiting Lan; Shixing Wang; Min Zhang; Ling Li; Huawei Liang

doi:10.3390/nano13050795

Optically Controlling Broadband Terahertz Modulator Based on Layer-Dependent PtSe₂ Nanofilms

Nanomaterials (Basel). 2023 Feb 21;13(5):795. doi: 10.3390/nano13050795.

Authors

Hong Su^{1

2}, Zesong Zheng^{1

2}, Zhisheng Yu^{1

2}, Shiping Feng^{1

2}, Huiting Lan^{1

2}, Shixing Wang^{1

2}, Min Zhang^{1

2}, Ling Li^{1

2}, Huawei Liang^{1

2}

Affiliations

¹ Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen 518060, China.
² Shenzhen Key Laboratory of Laser Engineering, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.

Abstract

In this paper, we propose an optically controlling broadband terahertz modulator of a layer-dependent PtSe₂ nanofilm based on a high-resistance silicon substrate. Through optical pump and terahertz probe system, the results show that compared with 6-, 10-, and 20-layer films, a 3-layer PtSe₂ nanofilm has better surface photoconductivity in the terahertz band and has a higher plasma frequency ω_p of 0.23 THz and a lower scattering time τ_s of 70 fs by Drude-Smith fitting. By the terahertz time-domain spectroscopy system, the broadband amplitude modulation of a 3-layer PtSe₂ film in the range of 0.1-1.6 THz was obtained, and the modulation depth reached 50.9% at a pump density of 2.5 W/cm². This work proves that PtSe₂ nanofilm devices are suitable for terahertz modulators.

Keywords: PtSe2; modulator; photoconductivity; terahertz.

Abstract

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