On‐Chip Synthesis of Quasi‐2D Semimetals from Multi‐Layer Chalcogenides

Abstract

Reducing the dimensions of materials from three to two, or quasi‐two, provides a fertile platform for exploring emergent quantum phenomena and developing next‐generation electronic devices. However, growing high‐quality, ultrathin, quasi2D materials in a templated fashion on an arbitrary substrate is challenging. Here, the study demonstrates a simple and reproducible on‐chip approach for synthesizing non‐layered, nanometer‐thick, quasi‐2D semimetals. In one implementation, this method starts with thin semiconducting InSe flakes of below 20 nm in thickness with nickel deposited on top, followed by a low‐temperature annealing step that results in a controlled transformation of the layered InSe to a non‐layered, crystalline semimetal via reaction with the laterally diffusing nickel. Atomic resolution microscopy reveals the transformed semimetal to be Ni3In2Se2 with a Kagome‐lattice structure. Moreover, it is demonstrated that this synthesis method is generalizable by transforming 2D layered chalcogenides such as SnS and SnSe employing Ni and Co to non‐layered semimetals, paving the way for engineering novel types of devices.