High electron mobility, quantum Hall effect and anomalous optical response in atomically thin InSe
High electron mobility, quantum Hall effect and anomalous optical response in atomically thin InSe
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DOI：
10.1038/nnano.2016.242
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发表时间：
2017-03-01
影响因子：
38.3
通讯作者：
Cao, Yang
中科院分区：
文献类型：
--
作者：
Bandurin, Denis A.;Tyurnina, Anastasia V.;Cao, Yang
十年来对二维(2D)原子晶体的深入研究表明，它们的性质可能与母体化合物(1，2)的性质有很大不同。这些差异是由量子限制引起的能带结构的变化决定的，如果潜在的晶格对称性改变(3，4)，这些差异是最明显的。在这里，我们报道了在惰性气氛下用六方氮化硼封装的几层InSe中的高质量2D电子气。在室温和液氦温度下，载流子迁移率分别超过10(3)cm(2)V~(-1)S(~(-1))和10(4)cm(2)V~(-1)S(~(-1))，从而观察到充分发展的量子霍尔效应。传导电子占据单一的二维子带，具有较小的有效质量。光致发光光谱表明，随着薄膜厚度的减小，薄膜的禁带宽度增加了0.5 eV以上。带边光学响应在单层中消失，这归因于单层的镜面对称性。封装的2D InSe扩大了石墨烯类半导体的家族，在质量方面与原子稀薄的二卤化物(5-7)和黑磷(8-11)具有竞争力。
A decade of intense research on two-dimensional (2D) atomic crystals has revealed that their properties can differ greatly from those of the parent compound(1,2). These differences are governed by changes in the band structure due to quantum confinement and are most profound if the underlying lattice symmetry changes(3,4). Here we report a high-quality 2D electron gas in few-layer InSe encapsulated in hexagonal boron nitride under an inert atmosphere. Carrier mobilities are found to exceed 10(3) cm(2) V-1 s(-1) and 10(4) cm(2) V-1 s(-1) at room and liquid-helium temperatures, respectively, allowing the observation of the fully developed quantum Hall effect. The conduction electrons occupy a single 2D subband and have a small effective mass. Photoluminescence spectroscopy reveals that the bandgap increases by more than 0.5 eV with decreasing the thickness from bulk to bilayer InSe. The band-edge optical response vanishes in monolayer InSe, which is attributed to the monolayer's mirror-plane symmetry. Encapsulated 2D InSe expands the family of graphene-like semiconductors and, in terms of quality, is competitive with atomically thin dichalcogenides(5-7) and black phosphorus(8-11).