A volatile polymer stamp for large-scale, etching-free, and ultraclean transfer and assembly of two-dimensional materials and its heterostructures

TL;DR

This paper introduces a volatile polymer stamping (VPS) method for large-scale, etching-free, and ultraclean transfer and assembly of 2D materials and heterostructures, improving interface quality and scalability.

Contribution

The VPS technique uses volatile PPA and hydrophobic PS to enable clean, large-scale transfer of 2D materials without chemical etching or contamination.

Findings

Achieves clean interfaces in 2D heterostructures

Enables large-scale transfer without chemical etching

Reduces contamination compared to traditional methods

Abstract

The intact transfer and assembly of two-dimensional (2D) materials and their heterostructures are critical for their integration into advanced electronic and optical devices. Herein, we report a facile technique called volatile polymer stamping (VPS) to achieve efficient transfer of 2D materials and assembly of large-scale heterojunctions with clean interfaces. The central feature of the VPS technique is the use of volatile polyphthalaldehyde (PPA) together with hydrophobic polystyrene (PS). While PS enables the direct delamination of 2D materials from hydrophilic substrates owing to water intercalation, PPA can protect 2D materials from solution attack and maintain their integrity during PS removal. Thereafter, PPA can be completely removed by thermal annealing at 180 {\deg}C. The proposed VPS technique overcomes the limitations of currently used transfer techniques, such as chemical etching during the delamination stage, solution tearing during cleaning, and contamination from polymer residues.