Ultraclean Interface of Metal Chalcogenides with Metal through Confined Interfacial Chalcogenization

Abstract

Acquisition of defect‐free transition metal dichalcogenides (TMDs) channels with clean heterojunctions has been a critical issue in production of TMD‐based functional electronic devices. Conventional approaches have synthesized high quality TMDs and transferred them onto a target substrate, and then applied the typical device fabrication processes. Unfortunately, those processes cause physical defects and chemical contamination in the TMD channels. Here, we propose a novel synthetic process of TMD thin films, named confined interfacial chalcogenization (CIC). In the proposed synthesis, a uniform TMD layer is created at the Au/transition metal (TM) interface by diffusion of chalcogen through the grain boundaries of the Au layer and reaction of chalcogen with the underlying TM. CIC allows for ultraclean heterojunctions with the metals, rapid synthesis of homo‐ and hetero‐structured TMDs, and in‐situ TMD channel formation in the last stage of device fabrication. We reveal the mechanism of TMD growth by the TM‐accelerated chalcogen diffusion, epitaxial growth of TMD on Au(111), and dependence of the growth rate on material species of chalcogen and TM. We demonstrate a 100% production yield of TMD‐based vertical memristors which exhibit excellent statistical concordance in device performance enabled by the ultraclean heterojunctions and superior uniformity in thickness and chemical composition. CIC proposed in this study represents a breakthrough in the synthesis of TMD thin films and also in the TMD‐based electronic device fabrication, marking a substantial step towards practical next‐generation integrated electronics.This article is protected by copyright. All rights reserved