Congratulation Jae Yol and Eun Sung for Adv. Mat. acceptance!
Title : Graphene Substrate for Van der Waals Epitaxy of Layer Structured Bismuth Antimony Telluride Thermoelectric Film
Authors : Eun Sung Kim, Jae-Yeol Hwang, Kyu Hyeong Lee, Hiromichi Ohta, Young Hee Lee, and SungWng Kim
Abstract : Facile and scalable fabrication method for the epitaxial growth of 2D layered materials via van der Waals epitaxy (vdWE) is realized by utilizing a high-quality mono-layer graphene as a 2D substrate. We report the epitaxial growth of layer-structured bismuth antimony telluride (BST) thermoelectric thin-film on graphene substrate as a proof of concept. The high-quality vdWE BST thin-film fabricated by pulsed laser deposition technique yields a high thermoelectric power factor of ~4.67 mW K-2 m-1 at 300 K, comparable to BST single crystal. This high thermoelectric performance originates from the characteristics of the vdWE film having a low defect density, no in-plane strain, and smooth vdW interface. The growth mechanism of this film proves that graphene substrate promotes the vdWE of layer structured BST film by initiating the formation of the first atomic Te layer on graphene through vdW interaction. We propose that the dangling bond-free mono-layer graphene can be used as a universal substrate for the vdWE of various 2D materials.