First-Principles Study of Adsorption of Alkali Metals (Li, Na, K) on Graphene

Oli, Biraj; Bhattarai, C.; Nepal, Bikash; Adhikari, Narayan Prasad

doi:10.1007/978-3-642-34216-5_51

Cited by 16 publications

(10 citation statements)

References 33 publications

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“…The values imply that sodium atom is bound to all the tested sites of the graphene sheet and the H site is the most favored one among them. This conclusion agrees with the previously reported results (Chan et al 2008;Oli et al 2013). The equilibrium distance of sodium atom from the surface of graphene sheet is found to be 2.32 Å for H Fig.…”

Section: Adsorption Of Sodium Atom On Graphenesupporting

confidence: 93%

“…It has been found that the binding energy of adsorbed metal atoms is size dependent and gets almost constant value beyond certain number of C atoms in graphene. Oli et al (2013) have reported rapid change in binding energy of alkali metal atoms (Li, Na and K) on graphene before reaching its saturation size, i.e., 48 number of carbon atoms. The quantities revealed by the authors for Na in passivated graphene structure of 16 carbon atoms of C 16 H 10 and 30 carbon atoms of C 30 H 14 are 0.32 eV and 0.72 eV, which are reasonably close to the present work of 18 (3 Â 3 supercell) and 32 (4 Â 4 supercell) atoms of graphene sheets, respectively (Oli et al 2013).…”

Section: Adsorption Of Sodium Atom On Graphenementioning

confidence: 99%

“…Oli et al (2013) have reported rapid change in binding energy of alkali metal atoms (Li, Na and K) on graphene before reaching its saturation size, i.e., 48 number of carbon atoms. The quantities revealed by the authors for Na in passivated graphene structure of 16 carbon atoms of C 16 H 10 and 30 carbon atoms of C 30 H 14 are 0.32 eV and 0.72 eV, which are reasonably close to the present work of 18 (3 Â 3 supercell) and 32 (4 Â 4 supercell) atoms of graphene sheets, respectively (Oli et al 2013). Ding et al (2011), on the other hand, have reported different trends of size dependency of binding energy for different atoms, while varying graphene supercell from 3 Â 3 to 4 Â 4.…”

Section: Adsorption Of Sodium Atom On Graphenementioning

confidence: 99%

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First-principles study of the interaction of hydrogen molecular on Na-adsorbed graphene

2014

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We have performed density functional theorybased first-principles calculations to study the stability, geometrical structures, and electronic/magnetic properties of pure graphene, sodium (Na)-adsorbed graphene and also the adsorption properties of H 2 -molecular ranging from one to five molecules on their preferred structures. Using the information of binding energy of Na at different adsorption sites of varying sized graphene supercell, it has been observed that hollow position is the most preferred site for Na adsorption, and the same in 3 Â 3 supercell has been used for further calculations. The band structure and density of states calculations have been performed to study the electronic/magnetic properties of Na-atom graphene. On comparing adsorption energy per H 2 -molecular in pure and Na-adsorbed graphene, we find that presence of Na atom, in general, enhances binding strength to H 2 -moleculars.

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Section: Adsorption Of Sodium Atom On Graphenesupporting

confidence: 93%

Section: Adsorption Of Sodium Atom On Graphenementioning

confidence: 99%

Section: Adsorption Of Sodium Atom On Graphenementioning

confidence: 99%

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First-principles study of the interaction of hydrogen molecular on Na-adsorbed graphene

2014

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“…This reduced size allows the K + ion to be adsorbed anywhere in the hexagonal structure of graphene. Theoretical investigations have also supported the preference of K + ions to reside in the hollow sites of the graphene honeycomb structure and transfer electrons to graphene . Therefore, potassium readily donates electrons to graphene, which significantly contributes to the n-type doping of graphene .…”

Section: Resultsmentioning

confidence: 89%

Bipolar Photoresponse of a Graphene Field-Effect Transistor Induced by Photochemical Reactions

Khan,

Elahi,

Hassan

et al. 2023

ACS Appl. Electron. Mater.

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Graphene is an air-friendly material that can be easily p-doped by oxygen; therefore, a stable, defect-free, and efficient graphene n-doping technique should be developed for achieving high performance in electronic and optoelectronic devices. In this study, we present a unique method for n-type chemical doping of monolayer graphene grown through chemical vapor deposition. The doping process is thoroughly examined using X-ray photoelectron spectroscopy, Raman spectroscopy, and ultraviolet photoelectron spectroscopy. The findings demonstrate that the use of KBr solution is highly effective in achieving n-type doping in monolayer graphene, offering promising prospects for its practical application. Also, we fabricated graphene field-effect transistors and studied their electrical properties before (pristine) and after doping the graphene channel with different KBr concentrations (0, 0.05, 0.15, 0.20, and 0.25 M) in dark and under deep-ultraviolet (DUV) light conditions. During graphene doping in the dark environment, the charge neutrality point (CNP) shifted toward negative back gate voltages and then saturated at 0.25 M. After photochemical doping under DUV light, CNP further shifted toward negative gate voltages with improved carrier mobility at the same molar concentration of 0.25 M. Additionally, the photodetectors are fabricated from pristine and doped graphene which demonstrated bipolar photoresponse, thereby, a transition of negative photocurrent to a positive photocurrent when the concentration of the KBr solution reached 0.20 M. Moreover, their response time decreased from 8 to 3.5 s with increasing KBr concentration from 0 to 0.30 M. Finally, the gate voltage-dependent broadband photoresponsivity of doped graphene (0.25 M) was investigated at different wavelengths (220, 365, 530, and 850 nm). Thus, the controlled doping-induced bidirectional photoresponse can provide a facile route for logic gate applications.

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“…The stable site of adsorption of Li and K on graphene has been reported as the hollow site, in which the adatoms are placed in the center of the hexagons of the graphene lattice [18,19,20]. In this configuration there is a higher coordination and lower charge density, so they can be accommodated closer to the surface, in comparison with other Li(K)-graphene…”

Section: Introductionmentioning

confidence: 99%

Transport properties of graphene in proximity with alkali metals

Peralta

Vaca-Chanatasig

Vera-Nieto

et al. 2022

J. Phys.: Conf. Ser.

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In this work, we propose the analysis of the electronic and transport properties of graphene decorated with Lithium and Potassium adatoms. We will study two inequivalent metal adsorption sites: the Top site, on top of a carbon atom of one sub-lattice of graphene; and the Hollow site, in the middle of a C6-unit. With this end, we will use an analytical Tight Binding Model, for graphene with adsorbate atoms of lithium and potassium, for the two different adsorption positions. Then, we use the Green’s function equation of motion method to calculate the corresponding band structures and density of states, and numerical calculations for the conductance are performed with the quantum transport simulation package of python (Kwant). We find that the bands are down shifted with respect to pristine graphene, indicating a doping with electrons. For the Top case, the AB symmetry breaking produced in this configuration, generates small bandgaps of approximately 170 meV for potassium and 220 meV for lithium. Finally, the conductance is shifted in energy in the same way as the bands, preserving its growing rate with the absolute value of the energy as for pristine graphene.

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First-Principles Study of Adsorption of Alkali Metals (Li, Na, K) on Graphene

Cited by 16 publications

References 33 publications

First-principles study of the interaction of hydrogen molecular on Na-adsorbed graphene

First-principles study of the interaction of hydrogen molecular on Na-adsorbed graphene

Bipolar Photoresponse of a Graphene Field-Effect Transistor Induced by Photochemical Reactions

Transport properties of graphene in proximity with alkali metals

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