Custom-Designed Glassy Carbon Tips for Atomic Force Microscopy

Abstract

Glassy carbon is a graphenic form of elemental carbon obtained from pyrolysis of carbon-rich precursor polymers that can be patterned using various lithographic techniques. It is electrically and thermally conductive, mechanically strong, light, corrosion resistant and easy to functionalize. These properties render it very suitable for Carbon-microelectromechanical systems (Carbon-MEMS) and nanoelectromechanical systems (Carbon-NEMS) applications. Here we report on the fabrication and characterization of fully operational, microfabricated glassy carbon nano-tips for Atomic Force Microscopy (AFM). These tips are 3D-printed on to micro-machined silicon cantilevers by Two-Photon Polymerization (2PP) of acrylate-based photopolymers (commercially known as IP-series resists), followed by their carbonization employing controlled pyrolysis, which shrinks the patterned structure by ≥98% in volume. Tip performance and robustness during contact and dynamic AFM modes are validated by morphology and wear tests. The design and pyrolysis process optimization performed for this work indicate which parameters require special attention when IP-series polymers are used for the fabrication of Carbon-MEMS and NEMS. Microstructural characterization of the resulting material confirms that it features a frozen percolated network of graphene sheets accompanied by disordered carbon and voids, similar to typical glassy carbons. The presented facile fabrication method can be employed for obtaining a variety of 3D glassy carbon nanostructures starting from the stereolithographic designs provided by the user.

Beyond 100 nm resolution in 3D laser lithography — Post processing solutions

“…During pyrolysis the resist molecules were decomposed and volatile species were removed from the chamber. Depending on the initial composition of the resist, the remaining elements rearrange to form a glassy carbon [21] (IP-DIP) or zirconium doped silica-carbon mixture [18] (SZ2080). The mass loss and rearrangement of the material cause the structures to shrink.…”

Glassy Carbon: A Promising Material for Micro- and Nanomanufacturing

“…Consequently, several commercially available photoresists, such as SU-8, AZ resists, mr-NIL resists (tradenames) are primarily composed these resins. Other resists include acrylate-based polymers [ 20 , 21 ] and various inorganic materials [ 22 , 23 , 24 ], and may entail further optimization when used in the nano-scale fabrication [ 13 , 15 ]. Some of these resists would yield none, or extremely small quantities of carbon on pyrolysis, which may have significantly different properties compared to glassy carbon.…”

Additive-Manufacturing of 3D Glass-Ceramics down to Nanoscale Resolution

“…Ultrafast lasers are extending their applications towards advanced nanoscale processing of materials 4,5 . Recently, additive manufacturing of 3D micro-/nano-structures followed by heat-treatment protocols for downscaling their dimensions while keeping their initial geometry was reported 6 , yet the attention was not paid in experimentally validated explanation of material conversion process 7 , thus the potential advantages besides resizing were not investigated 8,9 . Alternatively, the physical addition Figure 1.…”