Periodic micro/nanostructures on few-layer PtSe2 irradiated by femtosecond laser pulses

Abstract

We report on laser-induced periodic surface structures (LIPSS) on few-layer platinum diselenide (PtSe2) with a thickness of ∼5 nm, which has been realized by femtosecond laser pulse irradiation. Both low spatial frequency LIPSS (LSFL) and high spatial frequency LIPSS (HSFL) have been observed in our experiment. The LSFL period (∼1 μm) is near a central wavelength (1031 nm) of the femtosecond laser, which is much larger than the HSFL period (about 80–120 nm). Under specific laser-irradiation parameters, HSFL grooves can reach a depth of 5 nm below the PtSe2 surface, meaning that PtSe2 could be completely erased at these grooves. The confocal micro-Raman (μ-Raman) spectroscopy indicates that an intensity decrease of ∼25% of both the Eg (at ∼176 cm−1) and A1g (at ∼205 cm−1) vibrations has been observed in PtSe2 LIPSS, where there is an ∼0.27 cm−1 spectral redshift at the Eg Raman peak and an obvious spectral blueshift (∼0.89 cm−1) at the A1g Raman peak. Our work provides a convenient approach to fabricate periodic micro/nanostructures on a few-layer PtSe2, facilitating the development of functional photonic and optoelectronic devices based on two-dimensional (2D) materials.