Deterministic Exfoliation of <i>N</i>-Layer Transition Metal Dichalcogenides.

Abstract

We introduce a method based on gold-assisted exfoliation for deterministic, large-area exfoliation of few-layer transition metal dichalcogenides with precise control of layer number <i>N</i>. This technique uses a hybrid gold tape to create (<i>N</i> - 1)-layer terraces on a bulk crystal. The terraces, along with a continuous monolayer below, are subsequently cleaved using uniform gold tape to yield <i>N</i>-layer regions. The high electronic quality of the material is confirmed through the fabrication of field-effect transistors (FETs) from exfoliated monolayer, bilayer, and trilayer MoS₂, which exhibit carrier mobilities of up to 160 cm² V^-1 s^-1. This exfoliation technique can be combined with stacking and atomic layer etching to create a versatile toolkit to achieve more complex structures, including moiré heterostructures. This work demonstrates a robust and scalable route to engineering high-quality, few-layer 2D materials for electronic and quantum devices.