带隙
单层
材料科学
扫描隧道显微镜
阴极发光
激子
光致发光
高定向热解石墨
晶体缺陷
光谱学
费米能级
扫描隧道光谱
光电子学
分子物理学
凝聚态物理
纳米技术
化学
发光
物理
电子
量子力学
作者
Ricardo Javier Peña Román,Fabio Costa,Alberto Zobelli,Christine Elias,Pierre Valvin,Guillaume Cassabois,Bernard Gil,Alex Summerfield,T.S. Cheng,C. J. Mellor,Peter H. Beton,С. В. Новиков,Luiz Fernando Zagonel
出处
期刊:2D materials
[IOP Publishing]
日期:2021-07-07
卷期号:8 (4): 044001-044001
被引量:39
标识
DOI:10.1088/2053-1583/ac0d9c
摘要
Being a flexible wide band gap semiconductor, hexagonal boron nitride (h-BN) has great potential for technological applications like efficient deep ultraviolet light sources, building block for two-dimensional heterostructures and room temperature single photon emitters in the ultraviolet and visible spectral range. To enable such applications, it is mandatory to reach a better understanding of the electronic and optical properties of h-BN and the impact of various structural defects. Despite the large efforts in the last years, aspects such as the electronic band gap value, the exciton binding energy and the effect of point defects remained elusive, particularly when considering a single monolayer. Here, we directly measured the density of states of a single monolayer of h-BN epitaxially grown on highly oriented pyrolytic graphite, by performing low temperature scanning tunneling microscopy (STM) and spectroscopy (STS). The observed h-BN electronic band gap on defect-free regions is $(6.8\pm0.2)$ eV. Using optical spectroscopy to obtain the h-BN optical band gap, the exciton binding energy is determined as being of $(0.7\pm0.2)$ eV. In addition, the locally excited cathodoluminescence and photoluminescence show complex spectra that are typically associated to intragap states related to carbon defects. Moreover, in some regions of the monolayer h-BN we identify, using STM, point defects which have intragap electronic levels around 2.0 eV below the Fermi level.
科研通智能强力驱动
Strongly Powered by AbleSci AI