TY  - JOUR
AU  - Balog, Richard
AU  - Andersen, Mie
AU  - Jorgensen, Bjarke
AU  - Šljivančanin, Željko
AU  - Hammer, Bjork
AU  - Baraldi, Alessandro
AU  - Larciprete, Rosanna
AU  - Hofmann, Philip
AU  - Hornekaer, Liv
AU  - Lizzit, Silvano
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5531
AB  - Combined fast X-ray photoelectron spectroscopy and density functional theory calculations reveal the presence of two types of hydrogen adsorbate structures at the graphene/Ir(111) interface, namely, graphane-like islands and hydrogen dimer structures. While the former give rise to a periodic pattern, dimers tend to destroy the periodicity. Our data reveal distinctive growth rates and stability of both types of structures, thereby allowing one to obtain well-defined patterns of hydrogen clusters. The ability to control and manipulate the formation and size of hydrogen structures on graphene facilitates tailoring of its properties for a wide range of applications by means of covalent functionalization.
T2  - ACS Nano
T1  - Controlling Hydrogenation of Graphene on Ir(111)
VL  - 7
IS  - 5
SP  - 3823
EP  - 3832
DO  - 10.1021/nn400780x
ER  - 

@article{
author = "Balog, Richard and Andersen, Mie and Jorgensen, Bjarke and Šljivančanin, Željko and Hammer, Bjork and Baraldi, Alessandro and Larciprete, Rosanna and Hofmann, Philip and Hornekaer, Liv and Lizzit, Silvano",
year = "2013",
abstract = "Combined fast X-ray photoelectron spectroscopy and density functional theory calculations reveal the presence of two types of hydrogen adsorbate structures at the graphene/Ir(111) interface, namely, graphane-like islands and hydrogen dimer structures. While the former give rise to a periodic pattern, dimers tend to destroy the periodicity. Our data reveal distinctive growth rates and stability of both types of structures, thereby allowing one to obtain well-defined patterns of hydrogen clusters. The ability to control and manipulate the formation and size of hydrogen structures on graphene facilitates tailoring of its properties for a wide range of applications by means of covalent functionalization.",
journal = "ACS Nano",
title = "Controlling Hydrogenation of Graphene on Ir(111)",
volume = "7",
number = "5",
pages = "3823-3832",
doi = "10.1021/nn400780x"
}

Balog, R., Andersen, M., Jorgensen, B., Šljivančanin, Ž., Hammer, B., Baraldi, A., Larciprete, R., Hofmann, P., Hornekaer, L.,& Lizzit, S.. (2013). Controlling Hydrogenation of Graphene on Ir(111). in ACS Nano, 7(5), 3823-3832.
https://doi.org/10.1021/nn400780x

Balog R, Andersen M, Jorgensen B, Šljivančanin Ž, Hammer B, Baraldi A, Larciprete R, Hofmann P, Hornekaer L, Lizzit S. Controlling Hydrogenation of Graphene on Ir(111). in ACS Nano. 2013;7(5):3823-3832.
doi:10.1021/nn400780x .

Balog, Richard, Andersen, Mie, Jorgensen, Bjarke, Šljivančanin, Željko, Hammer, Bjork, Baraldi, Alessandro, Larciprete, Rosanna, Hofmann, Philip, Hornekaer, Liv, Lizzit, Silvano, "Controlling Hydrogenation of Graphene on Ir(111)" in ACS Nano, 7, no. 5 (2013):3823-3832,
https://doi.org/10.1021/nn400780x . .

TY  - JOUR
AU  - Nilsson, Louis
AU  - Šljivančanin, Željko
AU  - Balog, Richard
AU  - Xu, Wei
AU  - Linderoth, Trolle R.
AU  - Laegsgaard, Erik
AU  - Stensgaard, Ivan
AU  - Hammer, Bjork
AU  - Besenbacher, Flemming
AU  - Hornekaer, Liu
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4752
AB  - Combined scanning tunnelling microscopy measurements and density functional theory calculations reveal a method to induce linear structures of hydrogen adsorbates on graphite by covering the surface with a self-assembled molecular monolayer of cyanuric acid and exposing it to atomic hydrogen. The method can in principle be applied to obtain nanopattemed hydrogen structures on free standing graphene and graphene laid down on insulating substrates, hereby opening up for the possibility of substrate independent bandgap engineering of graphene. (C) 2012 Elsevier Ltd. All rights reserved.
T2  - Carbon
T1  - Linear hydrogen adsorbate structures on graphite induced by self-assembled molecular monolayers
VL  - 50
IS  - 5
SP  - 2052
EP  - 2056
DO  - 10.1016/j.carbon.2011.12.050
ER  - 

@article{
author = "Nilsson, Louis and Šljivančanin, Željko and Balog, Richard and Xu, Wei and Linderoth, Trolle R. and Laegsgaard, Erik and Stensgaard, Ivan and Hammer, Bjork and Besenbacher, Flemming and Hornekaer, Liu",
year = "2012",
abstract = "Combined scanning tunnelling microscopy measurements and density functional theory calculations reveal a method to induce linear structures of hydrogen adsorbates on graphite by covering the surface with a self-assembled molecular monolayer of cyanuric acid and exposing it to atomic hydrogen. The method can in principle be applied to obtain nanopattemed hydrogen structures on free standing graphene and graphene laid down on insulating substrates, hereby opening up for the possibility of substrate independent bandgap engineering of graphene. (C) 2012 Elsevier Ltd. All rights reserved.",
journal = "Carbon",
title = "Linear hydrogen adsorbate structures on graphite induced by self-assembled molecular monolayers",
volume = "50",
number = "5",
pages = "2052-2056",
doi = "10.1016/j.carbon.2011.12.050"
}

Nilsson, L., Šljivančanin, Ž., Balog, R., Xu, W., Linderoth, T. R., Laegsgaard, E., Stensgaard, I., Hammer, B., Besenbacher, F.,& Hornekaer, L.. (2012). Linear hydrogen adsorbate structures on graphite induced by self-assembled molecular monolayers. in Carbon, 50(5), 2052-2056.
https://doi.org/10.1016/j.carbon.2011.12.050

Nilsson L, Šljivančanin Ž, Balog R, Xu W, Linderoth TR, Laegsgaard E, Stensgaard I, Hammer B, Besenbacher F, Hornekaer L. Linear hydrogen adsorbate structures on graphite induced by self-assembled molecular monolayers. in Carbon. 2012;50(5):2052-2056.
doi:10.1016/j.carbon.2011.12.050 .

Nilsson, Louis, Šljivančanin, Željko, Balog, Richard, Xu, Wei, Linderoth, Trolle R., Laegsgaard, Erik, Stensgaard, Ivan, Hammer, Bjork, Besenbacher, Flemming, Hornekaer, Liu, "Linear hydrogen adsorbate structures on graphite induced by self-assembled molecular monolayers" in Carbon, 50, no. 5 (2012):2052-2056,
https://doi.org/10.1016/j.carbon.2011.12.050 . .

TY  - JOUR
AU  - Šljivančanin, Željko
AU  - Andersen, Mie
AU  - Hornekaer, Liv
AU  - Hammer, Bjork
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4324
AB  - The structure and stability of small hydrogen clusters adsorbed on graphene is studied by means of density functional theory (DFT) calculations. Clusters containing up to six H atoms are investigated systematically, with the clusters having either all H atoms on one side of the graphene sheet (cis-clusters) or having the H atoms on both sides in an alternating manner (trans-clusters). The most stable cis-clusters found have H atoms in ortho- and para-positions with respect to each other (two Hs on neighboring or diagonally opposite carbon positions within one carbon hexagon), while the most stable trans-clusters found have H atoms in ortho-trans-positions with respect to each other (two Hs on neighboring carbon positions, but on opposite sides of the graphene). Very stable trans-clusters with 13-22 H atoms were identified by optimizing the number of H atoms in ortho-trans-positions and thereby the number of closed, H-covered carbon hexagons. For the cis-clusters, the associative H(2) desorption was investigated. Generally, the desorption with the lowest activation energy proceeds via para-cis-dimer states, i.e., involving somewhere in the H clusters two H atoms that are positioned on opposite sites within one carbon hexagon. H(2) desorption from clusters lacking such H pairs is calculated to occur via hydrogen diffusion causing the formation of para-cis-dimer states. Studying the diffusion events showed a strong dependence of the diffusion energy barriers on the reaction energies and a general odd-even dependence on the number of H atoms in the cis-clusters.
T2  - Physical Review B: Condensed Matter and Materials Physics
T1  - Structure and stability of small H clusters on graphene
VL  - 83
IS  - 20
DO  - 10.1103/PhysRevB.83.205426
ER  - 

@article{
author = "Šljivančanin, Željko and Andersen, Mie and Hornekaer, Liv and Hammer, Bjork",
year = "2011",
abstract = "The structure and stability of small hydrogen clusters adsorbed on graphene is studied by means of density functional theory (DFT) calculations. Clusters containing up to six H atoms are investigated systematically, with the clusters having either all H atoms on one side of the graphene sheet (cis-clusters) or having the H atoms on both sides in an alternating manner (trans-clusters). The most stable cis-clusters found have H atoms in ortho- and para-positions with respect to each other (two Hs on neighboring or diagonally opposite carbon positions within one carbon hexagon), while the most stable trans-clusters found have H atoms in ortho-trans-positions with respect to each other (two Hs on neighboring carbon positions, but on opposite sides of the graphene). Very stable trans-clusters with 13-22 H atoms were identified by optimizing the number of H atoms in ortho-trans-positions and thereby the number of closed, H-covered carbon hexagons. For the cis-clusters, the associative H(2) desorption was investigated. Generally, the desorption with the lowest activation energy proceeds via para-cis-dimer states, i.e., involving somewhere in the H clusters two H atoms that are positioned on opposite sites within one carbon hexagon. H(2) desorption from clusters lacking such H pairs is calculated to occur via hydrogen diffusion causing the formation of para-cis-dimer states. Studying the diffusion events showed a strong dependence of the diffusion energy barriers on the reaction energies and a general odd-even dependence on the number of H atoms in the cis-clusters.",
journal = "Physical Review B: Condensed Matter and Materials Physics",
title = "Structure and stability of small H clusters on graphene",
volume = "83",
number = "20",
doi = "10.1103/PhysRevB.83.205426"
}

Šljivančanin, Ž., Andersen, M., Hornekaer, L.,& Hammer, B.. (2011). Structure and stability of small H clusters on graphene. in Physical Review B: Condensed Matter and Materials Physics, 83(20).
https://doi.org/10.1103/PhysRevB.83.205426

Šljivančanin Ž, Andersen M, Hornekaer L, Hammer B. Structure and stability of small H clusters on graphene. in Physical Review B: Condensed Matter and Materials Physics. 2011;83(20).
doi:10.1103/PhysRevB.83.205426 .

Šljivančanin, Željko, Andersen, Mie, Hornekaer, Liv, Hammer, Bjork, "Structure and stability of small H clusters on graphene" in Physical Review B: Condensed Matter and Materials Physics, 83, no. 20 (2011),
https://doi.org/10.1103/PhysRevB.83.205426 . .

TY  - JOUR
AU  - Balog, Richard
AU  - Jorgensen, Bjarke
AU  - Nilsson, Louis
AU  - Andersen, Mie
AU  - Rienks, Emile
AU  - Bianchi, Marco
AU  - Fanetti, Mattia
AU  - Laegsgaard, Erik
AU  - Baraldi, Alessandro
AU  - Lizzit, Silvano
AU  - Šljivančanin, Željko
AU  - Besenbacher, Flemming
AU  - Hammer, Bjork
AU  - Pedersen, Thomas G.
AU  - Hofmann, Philip
AU  - Hornekaer, Liv
PY  - 2010
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/3937
AB  - Graphene, a single layer of graphite, has recently attracted considerable attention owing to its remarkable electronic and structural properties and its possible applications in many emerging areas such as graphene-based electronic devices(1). The charge carriers in graphene behave like massless Dirac fermions, and graphene shows ballistic charge transport, turning it into an ideal material for circuit fabrication(2,3). However, graphene lacks a bandgap around the Fermi level, which is the defining concept for semiconductor materials and essential for controlling the conductivity by electronic means. Theory predicts that a tunable bandgap may be engineered by periodic modulations of the graphene lattice(4-6), but experimental evidence for this is so far lacking. Here, we demonstrate the existence of a bandgap opening in graphene, induced by the patterned adsorption of atomic hydrogen onto the Moire superlattice positions of graphene grown on an Ir(111) substrate.
T2  - Nature Materials
T1  - Bandgap opening in graphene induced by patterned hydrogen adsorption
VL  - 9
IS  - 4
SP  - 315
EP  - 319
DO  - 10.1038/NMAT2710
ER  - 

@article{
author = "Balog, Richard and Jorgensen, Bjarke and Nilsson, Louis and Andersen, Mie and Rienks, Emile and Bianchi, Marco and Fanetti, Mattia and Laegsgaard, Erik and Baraldi, Alessandro and Lizzit, Silvano and Šljivančanin, Željko and Besenbacher, Flemming and Hammer, Bjork and Pedersen, Thomas G. and Hofmann, Philip and Hornekaer, Liv",
year = "2010",
abstract = "Graphene, a single layer of graphite, has recently attracted considerable attention owing to its remarkable electronic and structural properties and its possible applications in many emerging areas such as graphene-based electronic devices(1). The charge carriers in graphene behave like massless Dirac fermions, and graphene shows ballistic charge transport, turning it into an ideal material for circuit fabrication(2,3). However, graphene lacks a bandgap around the Fermi level, which is the defining concept for semiconductor materials and essential for controlling the conductivity by electronic means. Theory predicts that a tunable bandgap may be engineered by periodic modulations of the graphene lattice(4-6), but experimental evidence for this is so far lacking. Here, we demonstrate the existence of a bandgap opening in graphene, induced by the patterned adsorption of atomic hydrogen onto the Moire superlattice positions of graphene grown on an Ir(111) substrate.",
journal = "Nature Materials",
title = "Bandgap opening in graphene induced by patterned hydrogen adsorption",
volume = "9",
number = "4",
pages = "315-319",
doi = "10.1038/NMAT2710"
}

Balog, R., Jorgensen, B., Nilsson, L., Andersen, M., Rienks, E., Bianchi, M., Fanetti, M., Laegsgaard, E., Baraldi, A., Lizzit, S., Šljivančanin, Ž., Besenbacher, F., Hammer, B., Pedersen, T. G., Hofmann, P.,& Hornekaer, L.. (2010). Bandgap opening in graphene induced by patterned hydrogen adsorption. in Nature Materials, 9(4), 315-319.
https://doi.org/10.1038/NMAT2710

Balog R, Jorgensen B, Nilsson L, Andersen M, Rienks E, Bianchi M, Fanetti M, Laegsgaard E, Baraldi A, Lizzit S, Šljivančanin Ž, Besenbacher F, Hammer B, Pedersen TG, Hofmann P, Hornekaer L. Bandgap opening in graphene induced by patterned hydrogen adsorption. in Nature Materials. 2010;9(4):315-319.
doi:10.1038/NMAT2710 .

Balog, Richard, Jorgensen, Bjarke, Nilsson, Louis, Andersen, Mie, Rienks, Emile, Bianchi, Marco, Fanetti, Mattia, Laegsgaard, Erik, Baraldi, Alessandro, Lizzit, Silvano, Šljivančanin, Željko, Besenbacher, Flemming, Hammer, Bjork, Pedersen, Thomas G., Hofmann, Philip, Hornekaer, Liv, "Bandgap opening in graphene induced by patterned hydrogen adsorption" in Nature Materials, 9, no. 4 (2010):315-319,
https://doi.org/10.1038/NMAT2710 . .

TY  - JOUR
AU  - Šljivančanin, Željko
AU  - Hammer, B
PY  - 2002
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/2544
AB  - Using density functional theory we have characterized O(2) dissociation on flat and stepped Pt(111) surfaces. The reactivity of the steps is significantly higher than that of the flat terraces. Inclusion of Ag monoatomic chains along the Pt steps modifies the reactivity of the Pt steps towards that of the flat Pt terraces. Our investigations reveal the reaction energetics and the geometries for the molecular precursor states (MPS), transition states (TS) and final states of the dissociating oxygen. Both the MPS and TS geometries on stepped Pt involve oxygen species at the top of the step with no oxygen atoms diffusing onto the lower terrace. We further find that the Ag chains mainly modify the adsorption and reaction bond strengths while they leave the MPS and TS geometries essentially unchanged. The high reactivity of the Pt steps is explained in terms of the coordinative unsaturation of the Pt step atoms which cause a highlying valence 5d-electron system. (C) 2002 Elsevier Science B.V. All rights reserved.
T2  - Surface Science
T1  - Oxygen dissociation at close-packed Pt terraces, Pt steps, and Ag-covered Pt steps studied with density functional theory
VL  - 515
IS  - 1
SP  - 235
EP  - 244
DO  - 10.1016/S0039-6028(02)01908-8
ER  - 

@article{
author = "Šljivančanin, Željko and Hammer, B",
year = "2002",
abstract = "Using density functional theory we have characterized O(2) dissociation on flat and stepped Pt(111) surfaces. The reactivity of the steps is significantly higher than that of the flat terraces. Inclusion of Ag monoatomic chains along the Pt steps modifies the reactivity of the Pt steps towards that of the flat Pt terraces. Our investigations reveal the reaction energetics and the geometries for the molecular precursor states (MPS), transition states (TS) and final states of the dissociating oxygen. Both the MPS and TS geometries on stepped Pt involve oxygen species at the top of the step with no oxygen atoms diffusing onto the lower terrace. We further find that the Ag chains mainly modify the adsorption and reaction bond strengths while they leave the MPS and TS geometries essentially unchanged. The high reactivity of the Pt steps is explained in terms of the coordinative unsaturation of the Pt step atoms which cause a highlying valence 5d-electron system. (C) 2002 Elsevier Science B.V. All rights reserved.",
journal = "Surface Science",
title = "Oxygen dissociation at close-packed Pt terraces, Pt steps, and Ag-covered Pt steps studied with density functional theory",
volume = "515",
number = "1",
pages = "235-244",
doi = "10.1016/S0039-6028(02)01908-8"
}

Šljivančanin, Ž.,& Hammer, B.. (2002). Oxygen dissociation at close-packed Pt terraces, Pt steps, and Ag-covered Pt steps studied with density functional theory. in Surface Science, 515(1), 235-244.
https://doi.org/10.1016/S0039-6028(02)01908-8

Šljivančanin Ž, Hammer B. Oxygen dissociation at close-packed Pt terraces, Pt steps, and Ag-covered Pt steps studied with density functional theory. in Surface Science. 2002;515(1):235-244.
doi:10.1016/S0039-6028(02)01908-8 .

Šljivančanin, Željko, Hammer, B, "Oxygen dissociation at close-packed Pt terraces, Pt steps, and Ag-covered Pt steps studied with density functional theory" in Surface Science, 515, no. 1 (2002):235-244,
https://doi.org/10.1016/S0039-6028(02)01908-8 . .