Floating Tip Nanolithography

TL;DR

This paper introduces a noncontact nanolithography technique using a laser-illuminated AFM tip hovering nanometers above surfaces, achieving high-resolution, reproducible surface modifications with diverse material removal mechanisms.

Contribution

It presents a novel floating tip nanolithography method combining laser illumination with AFM, enabling high-resolution, noncontact surface patterning with multiple removal mechanisms.

Findings

Achieved ~20 nm spatial resolution in surface modification.

Demonstrated high reproducibility compared to mechanical scratching.

Identified two mechanisms: thermal patterning and laser ablation.

Abstract

We demonstrate noncontact, high quality surface modification with spatial resolution of ~20 nm. The nanowriting is based on the interaction between the surface and the tip of an Atomic force microscope illuminated by a focused laser beam and hovering 1-4 nanometers above the surface without touching it. The floating tip nanowriting is compared to mechanical surface scratching, and is found to be much more reproducible, and of higher quality. In an Apertureless Scanning Near Field Optical Microscope geometry the tip is illuminated by a focused femtosecond laser, leading to two different, clearly identifiable mechanisms for removing material from the surface: when heated by the laser beam, the hot-tip thermally patterns the surface of low melting temperature soft materials, and when focused right at the apex of the sharp tip, the enhanced electric field of the laser beam causes ablation in high melting temperature metal films.