Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
ANTARES Beamline, Synchrotron SOLEIL, Université Paris-Saclay, L'Orme des Merisiers, Saint Aubin-BP 48, 91192, Gif sur, Yvette Cedex, France.
Adv Mater. 2018 Jul;30(30):e1800754. doi: 10.1002/adma.201800754. Epub 2018 Jun 11.
2D layered materials have emerged in recent years as a new platform to host novel electronic, optical, or excitonic physics and develop unprecedented nanoelectronic and energy applications. By definition, these materials are strongly anisotropic between the basal plane and cross the plane. The structural and property anisotropies inside their basal plane, however, are much less investigated. Black phosphorus, for example, is a 2D material that has such in-plane anisotropy. Here, a rare chemical form of arsenic, called black-arsenic (b-As), is reported as a cousin of black phosphorus, as an extremely anisotropic layered semiconductor. Systematic characterization of the structural, electronic, thermal, and electrical properties of b-As single crystals is performed, with particular focus on its anisotropies along two in-plane principle axes, armchair (AC) and zigzag (ZZ). The analysis shows that b-As exhibits higher or comparable electronic, thermal, and electric transport anisotropies between the AC and ZZ directions than any other known 2D crystals. Such extreme in-plane anisotropies can potentially implement novel ideas for scientific research and device applications.
二维层状材料近年来成为承载新颖电子、光学或激子物理并开发前所未有的纳米电子和能源应用的新平台。根据定义，这些材料在基面和穿过平面之间具有强烈的各向异性。然而，它们基面内的结构和性能各向异性的研究要少得多。例如，黑磷是一种具有这种面内各向异性的二维材料。在这里，报告了一种叫做黑砷（b-As）的砷的罕见化学形式，作为黑磷的表亲，是一种各向异性很强的层状半导体。对 b-As 单晶体的结构、电子、热和电输运性质进行了系统的表征，特别关注其在两个面内主轴（armchair，AC 和 zigzag，ZZ）上的各向异性。分析表明，b-As 在 AC 和 ZZ 方向之间表现出比任何其他已知二维晶体更高或可比的电子、热和电输运各向异性。这种极端的面内各向异性可能为科学研究和器件应用带来新的思路。
