Ultrafast and Resist-Free Nanopatterning of 2D Materials by Femtosecond Laser Irradiation

Abstract

The performance of two-dimensional (2D) materials is promising for electronic, photonic, and sensing devices since they possess large surface-to-volume ratios, high mechanical strength, and broadband light sensitivity. While significant advances have been made in synthesizing and transferring 2D materials onto different substrates, there is still the need for scalable patterning of 2D materials with nanoscale precision. Conventional lithography methods require protective layers such as resist or metals that can contaminate or degrade the 2D materials and deteriorate the final device performance. Current resist-free patterning methods are limited in throughput and typically require custom-made equipment. To address these limitations, we demonstrate the noncontact and resist-free patterning of platinum diselenide (PtSe2), molybdenum disulfide (MoS2), and graphene layers with nanoscale precision at high processing speed while preserving the integrity of the surrounding material. We use a commercial, off-the-shelf two-photon 3D printer to directly write patterns in the 2D materials with features down to 100 nm at a maximum writing speed of 50 mm/s. We successfully remove a continuous film of 2D material from a 200 μm × 200 μm substrate area in less than 3 s. Since two-photon 3D printers are becoming increasingly available in research laboratories and industrial facilities, we expect this method to enable fast prototyping of devices based on 2D materials across various research areas.

Patterned growth of two-dimensional atomic layer semiconductors

“…Thermal treatment offers a higher efficiency and less surface contamination than traditional etching processes that involve tedious fabrication steps and the direct contact of chemicals with the raw materials. 28,29 Fig. 5a shows that programmable laser patterning allows the creation of different desired patterns.…”

Dielectric breakdown and sub-wavelength patterning of monolayer hexagonal boron nitride using femtosecond pulses

“…In the quest for high harmonic generation in hBN, it may thus be advantageous to use diamond substrates to dissipate heat efficiently and avoid thermal damage under repetitive high intensity excitation. As another example, Stemme et al have demonstrated high-speed (50 mm s −1 ) and high-spatial-resolution (100 nm) patterning of PtSe 2 , MoS 2 , and graphene using a commercial femtosecond two-photon 3D printer [14]. Low-cost borosilicate glass wafers with a bandgap energy of 3-4 eV can serve as the supporting substrates for large-scale laser pattering of hBN instead of more expensive Al 2 O 3 or fused silica.…”

“…When the hatching distance is too small, hBN stripes become partially removed due to the positioning instability. Holes and line cuts demonstrated in figure 5 form the basic building blocks for more sophisticated structures and have plenty of room for improvement: Ablation resolution can be improved by using a shorter wavelength, narrower strip width can be obtained by a more stable translational stage or employing beam shaping techniques [12], and higher throughout can be obtained using a galvo scanner [14]. Moreover, a more effective recipe for cleaning PMMA residue [9] or a residue-free transferring agent such as PDMS [51] can be adopted to improve surface cleanness.…”

“…Compared to photo/e-beam lithography and ion/e-beam direct etching, laser direct writing avoids the use of resists [9], eliminates unintentional damage from backscattered electrons [10], forgoes the need of high vacuum [11], and is a high-speed technique for prototyping. Many groups have demonstrated fabrication of holes and grooves in low-bandgap 2D materials (including graphene, MoS 2 , and PtSe 2 ) using short-pulsed lasers with sub-wavelength resolution (∼100 nm) [12,13] and high speed (50 mm s −1 ) [14]. Similar features, if can be realized in hBN, can enable many important applications, such as metasurfaces (hole arrays and gratings) for mid-infrared polaritonic optical sensing [15], waveguides and micro-resonators [16], and patterning gate insulators and passivation layers.…”

Crystalline Orientation‐Tunable Growth of Hexagonal and Tetragonal 2H─PtSe2 Single‐Crystal Flakes

“…[1][2][3][4][5] Especially, due to the Pt vacancy, PtSe 2 exhibits the ferromagnetic property including distinct magnetoresistance, anomalous Hall effect, and layer-dependent magnetism. [6][7][8][9] Combining its environmental stability, [10][11][12] PtSe 2 has gained more attention for next generation nanoelectronic devices. [13][14][15][16][17][18][19] To date, a growing number of researches on PtSe 2 have prevailed and various synthesized methods have been reported successively.…”