Band gap measurements of monolayer h-BN and insights into carbon-related point defects
| Autor: | Peña Román, Ricardo Javier, 1990, Costa, Fábio Juvêncio Ramalho, 1993, Zagonel, Luiz Fernando, 1979 |
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| Přispěvatelé: | UNIVERSIDADE ESTADUAL DE CAMPINAS |
| Rok vydání: | 2021 |
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| Zdroj: | Repositório da Produção Científica e Intelectual da Unicamp Universidade Estadual de Campinas (UNICAMP) instacron:UNICAMP Repositório Institucional da Unicamp |
| Popis: | Agradecimentos: This work was supported by the Fundação de Amparoà Pesquisa do Estado de São Paulo (FAPESP) Projects 14/23399-9 and 18/08543-7. This work at Nottingham was supported by the Engineering and Physical Sciences Research Council UK (Grant Numbers EP/K040243/1 and EP/P019080/1). We also thank the University of Nottingham Propulsion Futures Beacon for funding towards this research. PHB thanks the Leverhulme Trust for the award of a Research Fellowship (RF-2019-460). This work was financially supported by the network GaNeX (ANR-11-LABX-0014), the ZEOLIGHT project (ANR-19-CE08-0016), and the BONASPES project (ANR-19-CE30-0007) Abstract: 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 +/- 0.2) eV. Using optical spectroscopy to obtain the h-BN optical band gap, the exciton binding energy is determined as being of (0.7 +/- 0.2) 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 FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado |
| Databáze: | OpenAIRE |
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