Manufacturing Chip-Scale 2D Monolayer Single Crystals through Wafer-Bonder-Assisted Transfer

Abstract

Significant progress has been made in growing large-area transition metal dichalcogenide (TMD) monolayers, but most rely on stitching small flakes, which can affect electronic and optical performance. High-quality single-crystal monolayers are needed for device applications. Here, we report a wafer-bonder-assisted transfer (WBAT) method to produce uniform, crack-free, single-crystal TMD monolayers over large areas. This technique integrates gold-tape exfoliation with wafer-scale bonding, enabling flake sizes over 10⁶ times larger than those from traditional Scotch tape exfoliation. Compared to hand-press transfer, WBAT yields higher-quality monolayers with fewer cracks, reduced strain, and over 2-fold improvement in photoluminescence uniformity, as confirmed by Raman and PL mapping. Fabricated field-effect transistor arrays show high mobility and on-off ratio. The WBAT method offers high yield, reproducibility, and compatibility with various 2D materials, heterostructures, and substrates, aligning with standard semiconductor processes. It provides a scalable solution for integrating high-quality TMD monolayers into next-generation electronic and optoelectronic devices.

Keywords: heterostack; large-area exfoliation; optical spectroscopy; transition metal dichalcogenides; wafer bonder.