Growth of Large‐Sized 2D Ultrathin SnSe Crystals with In‐Plane Ferroelectricity

Journal Article · 13 February 2023 · Advanced Electronic Materials

DOI: https://doi.org/10.1002/aelm.202201031 · OSTI ID:1924833

Chiu, Ming‐Hui ^[1]; Ji, Xiang ^[2]; Zhang, Tianyi ^[2]; Mao, Nannan ^[2]; Luo, Yue ^[3]; Shi, Chuqiao ^[4]; Zheng, Xudong ^[2]; Liu, Hongwei ^[5]; Han, Yimo ^[4]; Wilson, William L. ^[3]; Luo, Zhengtang ^[6]; Tung, Vincent ^[7]; Kong, Jing  ^[2]

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1. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA 02139 USA, Physical Sciences and Engineering King Abdullah University of Science and Technology Thuwal 23955‐6900 Saudi Arabia
2. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA 02139 USA
3. Center for Nanoscale Systems Harvard University Cambridge MA 02138 USA
4. Department of Materials Science and NanoEngineering Rice University Houston TX 77005 USA
5. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA 02139 USA, Department of Chemical and Biological Engineering The Hong Kong University of Science and Technology Kowloon Hong Kong 999077 P. R. China
6. Department of Chemical and Biological Engineering The Hong Kong University of Science and Technology Kowloon Hong Kong 999077 P. R. China
7. Physical Sciences and Engineering King Abdullah University of Science and Technology Thuwal 23955‐6900 Saudi Arabia, Department of Chemical System Engineering University of Tokyo Tokyo 113‐8654 Japan

Abstract Tin (II) selenide (SnSe) is an emerging 2D material with many intriguing properties, such as record‐high thermoelectric figure of merit (ZT), purely in‐plane ferroelectricity, and excellent nonlinear optical properties. To explore these functional properties and related applications, a crucial step is to develop controllable routes to synthesize large‐area, ultrathin, and high‐quality SnSe crystals. Physical vapor deposition (PVD) constitutes a reliable method to synthesize 2D SnSe, however, effects of various growth parameters have not yet been systematically investigated, and current PVD‐synthesized flakes are often thick (>10 nm) with small lateral sizes (<10 µm). In this work, high‐quality 2D SnSe crystals are synthesized via low‐pressure PVD, which display in‐plane ferroelectric domains observed by piezoresponse force microscopy and polarization‐dependent reflection spectroscopy. Detailed studies regarding the roles of various parameters are further carried out, including substrate pre‐annealing, growth duration, temperature, and pressure, which enable to rationally optimize the growth and obtain 2D SnSe crystals with lateral sizes up to ≈23.0 µm and thicknesses down to ≈2.0 nm (3–4 layers). This work paves the way for the controlled growth of large‐area 2D SnSe, facilitating the future exploration of many interesting multiferroic properties and applications with atomic thickness.

• Research Organization: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0020042
• OSTI ID: 1924833
• Journal Information: Advanced Electronic Materials, Journal Name: Advanced Electronic Materials Journal Issue: 4 Vol. 9; ISSN 2199-160X
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: United States
• Language: English