Acquisition of defect-free transition metal dichalcogenides (TMDs) channels with clean heterojunctions is a critical issue in the production of TMD-based functional electronic devices. Conventional approaches have transferred TMD onto a target substrate, and then apply the typical device fabrication processes. Unfortunately, those processes cause physical and chemical defects in the TMD channels. Here, a novel synthetic process of TMD thin films, named confined interfacial chalcogenization (CIC) is proposed. In the proposed synthesis, a uniform TMDlayer is created at the Au/transition metal (TM) interface by diffusion of chalcogen through the upper Au layer and the reaction of chalcogen with the underlying TM. CIC allows for ultraclean heterojunctions with the metals, synthesis of various homo- and hetero-structured TMDs, and in situ TMD channel formation in the last stage of device fabrication. The mechanism of TMD growth is revealed by the TM-accelerated chalcogen diffusion, epitaxial growth of TMD on Au(111). We demonstrated a wafer-scale TMD-based vertical memristors which exhibit excellent statistical concordance in device performance enabled by the ultraclean heterojunctions and superior uniformity in thickness. CIC proposed in this study represents a breakthrough in in TMD-based electronic device fabrication and marking a substantial step toward practical next-generation integrated electronics.
Keywords: epitaxy; memristors; transition metal dichalcogenides; ultraclean heterojunctions; vertical heterostructure.
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