Dielectric response and excitations of hydrogenated free-standing graphene

The conversion of semimetallic suspended graphene (Gr) to a large-gap semiconducting phase is realized by controlled adsorption of atomic hydrogen (deuterium) on free-standing Gr veils in nanoporous graphene. The effects of local rehybridization from sp² to sp³ chemical bonding are investigated by combining X-ray photoelectron spectroscopy and high-resolution electron energy-loss spectroscopy (HREELS) with ab-initio based modelling. The hydrogen adatoms on the C sites induce a stretching frequency, clearly identified in vibrational spectra thanks to the use of the D isotope, which is compatible with the predicted fingerprints of adsorption on both sides of Gr corresponding to the graphane configuration. HREELS of the deuterated samples shows a wide opening of the optical band gap, consistent with the modified spectral density observed in the valence band photoemission. The results are in agreement with ab-initio calculations by GW and Bethe-Salpeter equation approaches, showing a large quasiparticle gap opening and huge excitonic binding energy

Identifier
Source https://archive.materialscloud.org/record/2022.167
Metadata Access https://archive.materialscloud.org/xml?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai:materialscloud.org:1576
Provenance
Creator Betti, Maria Grazia; Marchiani, Dario; Tonelli, Andrea; Blundo, Elena; De Luca, Marta; Polimeni, Antonio; Frisenda, Riccardo; Mariani, Carlo; Jeong, Samuel; Ito, Yoshikazu; Cavani, Nicola; Biagi, Roberto; Gillespie, Peter N. O.; Bertran, Michael Hernandez; Bonacci, Miki; Molinari, Elisa; De Renzi, Valentina; Prezzi, Deborah
Publisher Materials Cloud
Publication Year 2022
Rights info:eu-repo/semantics/openAccess; Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode
OpenAccess true
Contact archive(at)materialscloud.org
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Language English
Resource Type Dataset
Discipline Materials Science and Engineering