Far-ultraviolet Absorption and Photoluminescence of Monolayer Graphene and Its Implications for Extended Red Emission

• Published in: The Astrophysical journal Vol. 901; no. 2; pp. 103 - 110
• Main Authors: Chou, Sheng-Lung, Lin, Meng-Yeh, Lin, Shu-Yu, Huang, Wen-Jian, Huang, Tzu-Ping, Lee, Yao-Chang, Wu, Yu-Jong
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01.10.2020; IOP Publishing
• Subjects: Astrochemistry; Astrophysics; Constraint modelling; Emission spectra; Excitation; Graphene; Interstellar emissions; Laboratory astrophysics; Lithium; Lithium fluoride; Monolayers; Near infrared radiation; Optical properties; Photoabsorption; Photoluminescence; Radiative processes; Substrates; Ultraviolet absorption
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/abb0e6

A monolayer graphene (GR) film on a lithium fluoride substrate was prepared to measure the optical properties of graphene in the far-UV region. The photoabsorption of the GR/LiF sample was universal in the spectral region of 105-350 nm, with an excitonic band near 130 nm and the absorbance of the GR/LiF sample at 10 K was ∼10% larger than that at 300 K. Upon far-UV excitation, the photoluminescence (PL) spectra of the GR/LiF sample showed a broad band at 630 nm at 300 K and two adjacent bands at 560 and 634 nm at 10 K. GR had a PL similar to the extended red emission (ERE) band, fulfilling the known observational model constraints of the light-driven process dominated by far-UV excitations, carbonaceous nature of ERE carriers, and broad emission in the red and near-IR regions. The result implies that graphene materials are promising candidates for carriers for the ERE.