Table 1.

Outline of the techniques for patterning SLBs, their resolutions, and disadvantages/advantages.

Technique	Patterning process	Lateralresolution	Advantages	Disadvantages	References
Micro-contact printing	Form of soft lithography that fabricates structures using elastomeric stamps, molds and conformable photomasks.	500 nm	No photo-reactive surfaced needed Resolution can reach tens of nm	Stamp deformation Shrinking/swelling of the stamp Ink diffusion	40,46
Photo-lithography	Uses light to transfer a pattern from a photo-mask to a light-sensitive chemical (photoresist), on a substrate.	<100 nm	Exact control of pattern shape and size Patterning over the entire surface	Requires extremely clean operating conditions Not effective for creating non-flat shapes	60
Scanning probe lithography	Set of nano-lithographic methods to pattern materials using scanning probes.	10 nm	High resolution as the process bypasses the diffraction limit.	Slower process in comparison to photolithography.	42,57,61
Electron beam lithography	A beam of electrons is scanned over a surface covered with an electron-sensitive resist, removing regions of exposed or non-exposed resist to draw a pattern.	<10 nm	High resolution Direct writing of custom patterns.	Beam drift and backscattering electrons can cause physical defects.	53,62
Multi-photon lithography(direct laser writing)	Structuring is achieved by direct fabrication using near infrared femtosecond lasers to induce polymerization at the focal point.	100 nm	Does not require a photo-mask or multiple processing steps. 3D fabrication	Short working distance required with objective lens limits the height of the fabricated structures.	45,58,59