Vapor-Phase Indium Intercalation in van der Waals Nanofibers of Atomically Thin W 6 Te 6 Wires

• Published in: ACS nano 2023-03, Vol.17 (6), p.5561-5569
• Main Authors: Natsui, Ryusuke, Shimizu, Hiroshi, Nakanishi, Yusuke, Liu, Zheng, Shimamura, Akito, Hung, Nguyen Tuan, Lin, Yung-Chang, Endo, Takahiko, Pu, Jiang, Kikuchi, Iori, Takenobu, Taishi, Okada, Susumu, Suenaga, Kazu, Saito, Riichiro, Miyata, Yasumitsu
• Format: Article
• Language: English
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.2c10997

One-dimensional (1D) conducting materials are of great interest as potential building blocks for integrated nanocircuits. Ternary 1D transition-metal chalcogenides, consisting of M X wires with intercalated A atoms (M = Mo or W; X = S, Se, or Te; A = alkali or rare metals, .), have attracted much attention due to their 1D metallic behavior, superconductivity, and mechanical flexibility. However, the conventional solid-state reaction usually produces micrometer-scale bulk crystals, limiting their potential use as nanoscale conductors. Here we demonstrate a versatile method to fabricate indium (In)-intercalated W Te (In-W Te ) bundles with a nanoscale thickness. We first prepared micrometer-long, crystalline bundles of van der Waals W Te wires using chemical vapor deposition and intercalated In into the crystal via a vapor-phase reaction. Atomic-resolution electron microscopy revealed that In atoms were surrounded by three adjacent W Te wires. First-principles calculations suggested that their wire-by-wire stacking can transform through postgrowth intercalation. Individual In-W Te bundles exhibited metallic behavior, as theoretically predicted. We further identified the vibrational modes by combining polarized Raman spectroscopy and nonresonant Raman calculations.