Vertically grown ultrathin Bi2SiO5 as high-κ single-crystalline gate dielectric

Jiabiao Chen; Zhaochao Liu; Xinyue Dong; Zhansheng Gao; Yuxuan Lin; Yuyu He; Yingnan Duan; Tonghuai Cheng; Zhengyang Zhou; Huixia Fu; Feng Luo; Jinxiong Wu

doi:10.1038/s41467-023-40123-1

Vertically grown ultrathin Bi₂SiO₅ as high-κ single-crystalline gate dielectric

Nat Commun. 2023 Jul 21;14(1):4406. doi: 10.1038/s41467-023-40123-1.

Authors

Affiliations

¹ Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensor Interdisciplinary Science Center, School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China.
² State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200093, China.
³ Center of Quantum Materials and Devices & College of Physics, Chongqing University, Chongqing, 401331, China.
⁴ Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensor Interdisciplinary Science Center, School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China. jxwu@nankai.edu.cn.

Abstract

Single-crystalline high-κ dielectric materials are desired for the development of future two-dimensional (2D) electronic devices. However, curent 2D gate insulators still face challenges, such as insufficient dielectric constant and difficult to obtain free-standing and transferrable ultrathin films. Here, we demonstrate that ultrathin Bi₂SiO₅ crystals grown by chemical vapor deposition (CVD) can serve as excellent gate dielectric layers for 2D semiconductors, showing a high dielectric constant (>30) and large band gap (~3.8 eV). Unlike other 2D insulators synthesized via in-plane CVD on substrates, vertically grown Bi₂SiO₅ can be easily transferred onto other substrates by polymer-free mechanical pressing, which greatly facilitates its ideal van der Waals integration with few-layer MoS₂ as high-κ dielectrics and screening layers. The Bi₂SiO₅ gated MoS₂ field-effect transistors exhibit an ignorable hysteresis (~3 mV) and low drain induced barrier lowering (~5 mV/V). Our work suggests vertically grown Bi₂SiO₅ nanoflakes as promising candidates to improve the performance of 2D electronic devices.