Direct observation of the band structure in bulk hexagonal boron nitride
Direct observation of the band structure in bulk hexagonal boron nitride
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DOI：
10.1103/physrevb.95.085410
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发表时间：
2017-02-08
影响因子：
3.7
通讯作者：
Ouerghi, Abdelkarim
中科院分区：
文献类型：
--
作者：
Henck, Hugo;Pierucci, Debora;Ouerghi, Abdelkarim
纳米器件应用的一个有前途的途径依赖于石墨烯和过渡金属二硫属化物与六方氮化硼（h-BN）的缔合。由于其绝缘性质，h-BN已经成为石墨烯基电子器件的天然衬底和栅极电介质。然而，体相h-BN的一些基本性质仍然不清楚。例如，费米能级的能带结构和位置还没有被实验解决。在这里，我们报告了一个直接观察的抛物型色散的h-BN晶体使用高分辨率角分辨光电子能谱（ARPES）。我们发现，在外延石墨烯上的h-BN剥离能够克服使用ARPES与绝缘材料的技术困难。我们在恒定能量的强度图的三角翘曲。价带最大值位于K点附近，低于费米能级2.5 eV，从而证实了典型h-BN的残余p型特征。
A promising route towards nanodevice applications relies on the association of graphene and transition metal dichalcogenides with hexagonal boron nitride (h-BN). Due to its insulating nature, h-BN has emerged as a natural substrate and gate dielectric for graphene-based electronic devices. However, some fundamental properties of bulk h-BN remain obscure. For example, the band structure and the position of the Fermi level have not been experimentally resolved. Here, we report a direct observation of parabolic dispersions of h-BN crystals using high-resolution angle-resolved photoemission spectroscopy (ARPES). We find that h-BN exfoliation on epitaxial graphene enables overcoming the technical difficulties of using ARPES with insulating materials. We show trigonal warping of the intensity maps at constant energy. The valence-band maxima are located around the K points, 2.5 eV below the Fermi level, thus confirming the residual p-type character of typical h-BN.