Symmetry-Driven Band Gap Engineering in Hydrogen Functionalized Graphene

Band gap engineering in hydrogen functionalized graphene is demonstrated by changing the symmetry of the functionalization structures. Small differences in hydrogen adsorbate binding energies on graphene on Ir(111) allow tailoring of highly periodic functionalization structures favoring one distinct region of the moiré supercell. Scanning tunneling microscopy and X-ray photoelectron spectroscopy measurements show that a highly periodic hydrogen functionalized graphene sheet can thus be prepared by controlling the sample temperature (Ts) during hydrogen functionalization. At deposition temperatures of Ts = 645 K and above, hydrogen adsorbs exclusively on the HCP regions of the graphene/Ir(111) moiré structure. This finding is rationalized in terms of a slight preference for hydrogen clusters in the HCP regions over the FCC regions, as found by density functional theory calculations. Angle-resolved photoemission spectroscopy measurements demonstrate that the preferential functionalization of just one region of the moiré supercell results in a band gap opening with very limited associated band broadening. Thus, hydrogenation at elevated sample temperatures provides a pathway to efficient band gap engineering in graphene via the selective functionalization of specific regions of the moiré structure.

Čabo, Antonija GrubišićAarhus University (författare)
Balog, RichardBasque Foundation for Science (författare)
Kyhl, LineAarhus University (författare)
Groves, Michael N.Aarhus University (författare)
Cassidy, Andrew MartinAarhus University (författare)
Bruix, AlbertAarhus University (författare)
Bianchi, MarcoAarhus University (författare)
Dendzik, MaciejAarhus University (författare)
Arman, Mohammad AlifLund University,Lunds universitet,Synkrotronljusfysik,Fysiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Synchrotron Radiation Research,Department of Physics,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)slju-afa (författare)
Lammich, LutzAarhus University (författare)
Pascual, José IgnacioBasque Foundation for Science (författare)
Knudsen, JanLund University,Lunds universitet,MAX IV-laboratoriet,Synkrotronljusfysik,Fysiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,MAX IV Laboratory,Synchrotron Radiation Research,Department of Physics,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)slju-jks (författare)
Hammer, BjørkAarhus University (författare)
Hofmann, PhilipAarhus University (författare)
Hornekaer, LivAarhus University (författare)
Aarhus UniversityBasque Foundation for Science (creator_code:org_t)

Ingår i:ACS Nano: American Chemical Society (ACS)10:12, s. 10798-108071936-08511936-086X

Av författaren/redakt...: Jørgensen, Jakob ...; Čabo, Antonija G ...; Balog, Richard; Kyhl, Line; Groves, Michael ...; Cassidy, Andrew ...; visa fler...; Bruix, Albert; Bianchi, Marco; Dendzik, Maciej; Arman, Mohammad ...; Lammich, Lutz; Pascual, José Ig ...; Knudsen, Jan; Hammer, Bjørk; Hofmann, Philip; Hornekaer, Liv; visa färre...

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