Wu Chia-Hsing, Huang Yu-Che, Ho Yen-Teng, Chang Shu-Jui, Wu Ssu-Kuan, Huang Ci-Hao, Chou Wu-Ching, Yang Chu-Shou
International College of Semiconductor Technology, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Nanomaterials (Basel). 2022 Jul 15;12(14):2435. doi: 10.3390/nano12142435.
Single-phase two-dimensional (2D) indium monoselenide (γ-InSe) film is successfully grown via solid phase epitaxy in the molecular beam epitaxy (MBE) system. Having high electron mobility and high photoresponsivity, ultrathin 2D γ-InSe semiconductors are attractive for future field-effect transistor and optoelectronic devices. However, growing single-phase γ-InSe film is a challenge due to the polymorphic nature of indium selenide (γ-InSe, α-InSe, β-InSe, γ-InSe, etc.). In this work, the 2D α-InSe film was first grown on a sapphire substrate by MBE. Then, the high In/Se ratio sources were deposited on the α-InSe surface, and an γ-InSe crystal emerged via solid-phase epitaxy. After 50 min of deposition, the initially 2D α-InSe phase was also transformed into a 2D γ-InSe crystal. The phase transition from 2D α-InSe to γ-InSe was confirmed by Raman, XRD, and TEM analysis. The structural ordering of 2D γ-InSe film was characterized by synchrotron-based grazing-incidence wide-angle X-ray scattering (GIWAXS).
通过分子束外延（MBE）系统中的固相外延成功生长出单相二维（2D）硒化铟（γ-InSe）薄膜。超薄二维γ-InSe半导体具有高电子迁移率和高光响应性，对未来的场效应晶体管和光电器件具有吸引力。然而，由于硒化铟（γ-InSe、α-InSe、β-InSe、γ-InSe等）的多晶型性质，生长单相γ-InSe薄膜是一项挑战。在这项工作中，首先通过MBE在蓝宝石衬底上生长二维α-InSe薄膜。然后，将高In/Se比的源沉积在α-InSe表面，通过固相外延形成γ-InSe晶体。沉积50分钟后，最初的二维α-InSe相也转变为二维γ-InSe晶体。通过拉曼光谱、X射线衍射（XRD）和透射电子显微镜（TEM）分析证实了从二维α-InSe到γ-InSe的相变。二维γ-InSe薄膜的结构有序性通过基于同步加速器的掠入射广角X射线散射（GIWAXS）进行表征。
