第五主族材料:从三维到单层材料

Group V materials:From bulk to monolayer

自从2004年石墨烯的成功制备,近10年以来,见证了二维材料在凝聚态物理、材料科学以及化学等领域的飞速发展.尽管石墨烯具有迁移率高、透光性好、柔韧度大等优点,但当其作为半导体材料时,却是一个零带隙半导体.因而,研究者便将目光集中到与之相邻的一族元素—第五主族层状结构的磷、砷、锑和铋.剥离出二维结构的第五主族纳米材料(磷烯、砷烯、锑烯和铋烯)展现了许多新奇的、前所未有的特性,在电子器件与光电纳米器件的应用上有着无限的前景和价值.本文将从理论计算模拟和实验进展两个方面,系统总结磷烯、砷烯、锑烯和铋烯的物理、化学性质以及相关研究的进展.最后,基于磷烯、砷烯、锑烯和铋烯材料目前的研究现状,将对其在未来的研究前景和探索方向进行展望.

Since graphene has been fabricated successfully in 2004, two dimensional（2D） materials have received a great attention because of their exceptional properties and novel applications. However, there are problems exist in traditional 2D materials. Graphene, as the very first 2D material, is a zero band-gap semiconductor which results in low on-off ratio. Hexagonal boron nitride（h BN） has a large band-gap around 6 eV that can be considered as insulator. Monolayer Mo S2 also is an important 2D material, but the relative low mobility limits its applications. In 2014, few and single layer black phosphorus（BP） was achieved by mechanical exfoliation. And p-type field effect transistors（FETs） based on few-layer phosphorene also have been fabricated successfully. The BP FETs exhibit high mobility value up to ~1000 cm2/（V s） at room temperature. Besides, a direct band-gap of ~2 eV indicates that monolayer BP possess a high on/off ratio. These two advantages make phosphorene a promising FET material which is the most desirable application of 2D materials. Despite the superior properties, phosphorene still has its problems. When exposure to air, phosphorene tends to degradation and breakdown which restrict their applications in electronic and optoelectronic devices. The production of monolayer BP provokes wondering if other elements from group V can be the potential elemental 2D crystals. Elements from group V beyond phosphorus should be more chemical steady than phosphorus. And like black phosphorus, grey arsenic, grey antimony and rhombohedral bismuth are the most stable phase of these three elements with layer structures. For these two reasons, there are many reports about arsenic, antimony and bismuth in 2D structures. In this paper, we review the development of group V elemental materials from three-dimensional（3D） to 2D. Bulk arsenic and antimony are narrow semiconductor and semimetal, respectively. Differ from black phosphorus with orthorhombic structure, grey arsenic and grey antimony possess rhombohedral structures. Through density functional theory（DFT） calculation, the phonon spectra proved the thermodynamics stabilities of monolayer As and Sb. And an intriguing indirect-to-direct band-gap transition at a relatively small critical strain has been reported. After that, a lot of properties of group V elemental 2D materials are reported. Theoretically, their properties can be manipulated by functionalization, strain and electric field to applying magnetic, electronic, topological and thermoelectrical materials. Experimentally, arsenene and antimonene can be produced via liquid exfoliation, van der Waals epitaxy, mechanical exfoliation, plasma-assisted process and molecular beam epitaxy. Based on the antimonene fabricated by liquid exfoliation, an unexpected nonlinear optical limiting property which is even better than graphene in the visible and near infrared region（532–2000 nm） and high transmission（more than 80%） when dispersed in solutions or high concentration doped in Ormosil gel glasses. This might lead to many promising applications in nonlinear optical fields such as laser protection.