Nanopatterning of multicomponent van der Waals heterostructures using atomic force microscopy

TL;DR

This paper introduces an AFM-based nanopatterning technique for multilayer van der Waals heterostructures that achieves high resolution without the need for special environments, expanding capabilities for nanoscale device fabrication.

Contribution

It presents a novel electrode-free AFM nanopatterning method that operates at ambient conditions with high resolution for various multilayer vdW heterostructures.

Findings

Achieves $ extless$100 nm etching resolution.

Operates without humidity control.

Compatible with multiple vdW materials.

Abstract

Multilayer van der Waals (vdW) heterostructures have become an important platform in which to study novel fundamental effects emerging at the nanoscale. Standard nanopatterning techniques relying on electron-beam lithography and reactive ion etching, widely applied to pattern such heterostructures, however, impose some limitations on the edge accuracy and resolution, as revealed through numerous experiments with vdW quantum dots and point contacts. Here we present an alternative approach for electrode-free nanopatterning of thick multilayer vdW heterostructures based on atomic force microscopy (AFM). By applying an AC voltage of a relatively small frequency (1-10 kHz) between the sharp platinum tip and the substrate, we realize high-resolution ($\lesssim 100$ nm) etching of thick multicomponent heterostructures if the latter are deposited onto graphite slabs. Importantly, unlike more conventional electrode-free local anodic oxidation, our method does not require a special environment with excess humidity, can be applied at ambient conditions, and enables the patterning of multilayer heterostructures composed of graphene, graphite, hexagonal boron nitride (hBN), NbSe$_{2}$, WSe$_{2}$, and more.