Anomalous Pressure Characteristics of Defects in Hexagonal Boron Nitride Flakes.
ACS Nano
; 12(7): 7127-7133, 2018 Jul 24.
Article
em En
| MEDLINE
| ID: mdl-29957923
ABSTRACT
Research on hexagonal boron nitride (hBN) has been intensified recently due to the application of hBN as a promising system of single-photon emitters. To date, the single photon origin remains under debate even though many experiments and theoretical calculations have been performed. We have measured the pressure-dependent photoluminescence (PL) spectra of hBN flakes at low temperatures by using a diamond anvil cell device. The absolute values of the pressure coefficients of discrete PL emission lines are all below 15 meV/GPa, which is much lower than the pressure-induced 36 meV/GPa redshift rate of the hBN bandgap. These PL emission lines originate from atom-like localized defect levels confined within the bandgap of the hBN flakes. Interestingly, the experimental results of the pressure-dependent PL emission lines present three different types of pressure responses corresponding to a redshift (negative pressure coefficient), a blueshift (positive pressure coefficient), or even a sign change from negative to positive. Density functional theory calculations indicate the existence of competition between the intralayer and interlayer interaction contributions, which leads to the different pressure-dependent behaviors of the PL peak shift.
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Coleções:
01-internacional
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MEDLINE
Idioma:
En
Revista:
ACS Nano
Ano de publicação:
2018
Tipo de documento:
Article