Miki Bonacci^1,2*, Elisa Molinari^1,2, Deborah Prezzi²

1 FIM Department, University of Modena and Reggio Emilia, Via Campi 213/a, Modena, Italy

2 S3 Center, Istituto Nanoscienze, CNR, Via Campi 213/a, Modena, Italy

* Corresponding authors emails: miki.bonacci@nano.cnr.it

DOI10.24435/materialscloud:9b-34 [version v2]

Publication date: Mar 10, 2023

How to cite this record

Miki Bonacci, Elisa Molinari, Deborah Prezzi, Dielectric response and excitations of hydrogenated free-standing graphene, Materials Cloud Archive 2023.40 (2023), doi: 10.24435/materialscloud:9b-34.

Description

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

Materials Cloud sections using this data

Files

File name	Size	Description
raw_input_output.tar.gz MD5md5:5794bf06943ae6112e85613802ad6635	613.4 KiB	Raw Yambo and quantumESPRESSO inputs and outputs
README.txt MD5md5:f05dbc1840a98a5751b255d722e69728	980 Bytes	Information on this entry
structures.tar.gz MD5md5:b05b0c32429a6de1447af8dcdedbc30e	1.2 KiB	Structures of the H-graphene prototypes. xsf format.
optical_gaps.json MD5md5:320659a3d6a5afc07fae5040478a0761	267 Bytes	BSE (and GW) gaps for all the systems studied.

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External references

Keywords

BIG-MAP BSE first principles hydrogenated graphene nanoporous graphene MaX Yambo code density-functional theory high-resolution electron energy-loss spectroscop HREELS