Structural and dynamical properties of water adsorption on PtO2(001)

The structural, dynamical and electronic properties of water molecules on the β-PtO₂(001) surface has been studied using first-principles calculations. For both water monomer and monolayer, the adsorption energies are found to be three to five times larger than that of water adsorption on the Pt surface, and the dissociative adsorption configurations are energetically more stable. The adsorption energies are positively correlated with the charge transfer between the water molecule and the substrate, and the charge-rebalance between the Pt and O atoms of β-PtO₂ upon water adsorption. More interestingly, an exceptionally large redshift is observed in the OH stretching mode of the adsorbed water monomer, due to the very strong hydrogen bonding with the substrate. The strong water–substrate interactions have significant effects on the molecular orbitals of the chemisorbed water molecules.

The structural, dynamical and electronic properties of water molecules on the β-PtO₂(001) surface has been studied using first-principles calculations.     

Chemical functionalization of the ZnO monolayer: structural and electronic properties

Two-dimensional zinc oxide (ZnO) materials have been extensively investigated both experimentally and theoretically due to their novel properties and promising applications in optoelectronic and spintronic devices; however, how to tune the electronic property of the ZnO monolayer is still a challenge. Herein, employing the first-principles calculations, we explored the effect of chemical functionalization on the structural and electronic properties of the ZnO monolayer. The results demonstrated that the hydrogenated-, fluorinated- or Janus-functionalized ZnO monolayers were thermodynamically and mechanically stable except for the fully hydrogenated ZnO monolayer. The band gap of the ZnO monolayer could be effectively modulated by hydrogenation or fluorination, which varied from 0 to 2.948 eV, as obtained by the PBE functional, and from 0 to 5.114 eV, as obtained by the HSE06 functional. In addition, a nonmagnetic metal → nonmagnetic semiconductor transition was achieved after hydrogenation, whereas a transition from a magnetic half-metal to nonmagnetic semiconductor occurred after fluorination of the ZnO monolayer. These results demonstrate that tunability of the electronic properties of the ZnO monolayer can be realized by chemical functionalization for future nanoelectronic device applications.

After hydrogenation or fluorination, the band gap of the ZnO monolayer can be effectively modulated, and a nonmagnetic metal or magnetic half-metal → non-magnetic semiconductor transition can be achieved.     

The mechanical,electronic, optical and thermoelectric properties of two-dimensional honeycomb-like of XSb (X = Si,Ge, Sn) monolayers: a first-principles calculations

Herein, by using first-principles calculations, we demonstrate a two-dimensional (2D) of XSb (X = Si, Ge, and Sn) monolayers that have a honey-like crystal structure. The structural, mechanical, electronic, thermoelectric efficiency, and optical properties of XSb monolayers are studied. Ab initio molecular dynamic simulations and phonon dispersion calculations suggests their good thermal and dynamical stabilities. The mechanical properties of XSb monolayers shows that the monolayers are considerably softer than graphene, and their in-plane stiffness decreases from SiSb to SnSb. Our results shows that the single layers of SiSb, GeSb and SnSb are semiconductor with band gap of 1.48, 0.77 and 0.73 eV, respectively. The optical analysis illustrate that the first absorption peaks of the SiSb, GeSb and SnSb monolayers along the in-plane polarization are located in visible range of light which may serve as a promising candidate to design advanced optoelectronic devices. Thermoelectric properties of the XSb monolayers, including Seebeck coefficient, electrical conductivity, electronic thermal conductivity, power factor and figure of merit are calculated as a function of doping level at temperatures of 300 K and 800 K. Between the studied two-dimensional materials (2DM), SiSb single layer may be the most promising candidate for application in the thermoelectric generators.

Herein, by using first-principles calculations, we demonstrate a two-dimensional (2D) of XSb (X = Si, Ge, and Sn) monolayers that have a honey-like crystal structure.     

Anisotropic optical properties induced by uniaxial strain of monolayer C3N: a first-principles study

The optical properties, structural properties and electronic properties of a new two-dimensional (2D) monolayer C₃N under different strains are studied in this paper by using first-principles calculations. The applied strain includes in-layer biaxial strain and uniaxial strain. The monolayer C₃N is composed of a number of hexagonal C rings with N atoms connecting them. It is a stable indirect band gap 2D semiconductor when the strain is 0%. It could maintain indirect semiconductive character under different biaxial and uniaxial strains from ε = −10% to ε = 10%. As for its optical properties, when the uniaxial strain is applied, the absorption and reflectivity along the armchair and zigzag directions exhibit an anisotropic property. However, an isotropic property is presented when the biaxial strain is applied. Most importantly, both uniaxial tensile strain and biaxial tensile strain could cause the high absorption coefficient of monolayer C₃N to be in the deep ultraviolet region. This study implies that strain engineering is an effective approach to alter the electronic and optical properties of monolayer C₃N. We suggest that monolayer C₃N could be suitable for applications in optoelectronics and nanoelectronics.

The optical properties, structural properties and electronic properties of a new two-dimensional (2D) monolayer C₃N under different strains are studied in this paper by using first-principles calculations.     

Antiferromagnetic ordering in the TM-adsorbed AlN monolayer (TM = V and Cr)

In this work, the effects of transition metal (TM = V and Cr) adsorption on AlN monolayer electronic and magnetic properties are investigated using first-principles density functional theory (DFT) calculations. TMs prefer to be adsorbed on-top of a bridge position as indicated by the calculated adsorption energy. V adatoms induce half-metallicity, while Cr adatoms metallize the monolayer. The magnetic properties are produced mainly by the V and Cr adatoms with magnetic moments of 3.72 and 4.53 μ_B, respectively. Further investigation indicates that antiferromagnetic (AFM) ordering is energetically more favorable than ferromagnetic (FM) ordering. In both cases, the AFM state is stabilized upon increasing adatom coverage. The AlN monolayer becomes an AFM semiconductor with 0.5 ML of V adatom, and metallic nature is induced with 1.0 ML. Meanwhile, the degree of metallicity increases with increasing Cr adatoms. Results reported herein may provide a feasible new approach to functionalize AlN monolayers for spintronic applications.

The effects of transition metal (TM = V and Cr) adsorption on AlN monolayer electronic and magnetic properties are investigated using first-principles density functional theory calculations.     

Structural,elastic, and electronic properties of chemically functionalized boron phosphide monolayer

Surface functionalization is one of the useful techniques for modulating the mechanical and electronic properties of two-dimensional systems. In the present study, we investigate the structural, elastic, and electronic properties of hexagonal boron phosphide monolayer functionalized by Br and Cl atoms using first-principles predictions. Once surface-functionalized with Br/Cl atoms, the planar structure of BP monolayer is transformed to the low-buckled lattice with the bucking constant of about 0.6 Å for all four configurations of functionalized boron phosphide, i.e., Cl–BP–Cl, Cl–BP–Br, Br–BP–Cl, and Br–BP–Br. The stability of functionalized BP monolayers is confirmed via their phonon spectra analysis and ab initio molecular dynamics simulations. Our calculations indicate that the functionalized BP monolayers possess a fully isotropic elastic characteristic with the perfect circular shape of the angle-dependent Young''s modulus and Poisson''s ratio due to the hexagonal symmetry. The Cl–BP–Cl is the most stiff with the Young''s modulus C_2D = 43.234 N m⁻¹. All four configurations of the functionalized boron phosphide are direct semiconductors with a larger band gap than that of a pure BP monolayer. The outstanding stability, isotropic elastic properties, and moderate band gap make functionalized boron phosphide a very intriguing candidate for next-generation nanoelectromechanical devices.

Surface functionalization is one of the useful techniques for modulating the mechanical and electronic properties of two-dimensional systems.     

A study of the density of states of ZnCoO:H from resistivity measurements

Understanding the electronic band structure and density of states (DOS) of a material and their relationship to the associated electronic transport properties is the starting point for optimizing the performance of a device and its technological applications. In a hydrogenated Zn_0.8Co_0.2O (ZnCoO:H) film with an inverted thin-film transistor structure, we found ambipolar behavior, which is shown in many field-effect devices based on graphene, graphene nanoribbons, and organic semiconductors. In this study, to obtain information on the DOS of ZnCoO:H to explain the ambipolar behavior in terms of the carrier density and type, resistivity and magnetoresistance measurements of a ZnCoO:H film were performed at 5 K. Our proposed DOS representation of ZnCoO:H explains qualitatively the experimental observations of carrier density modulation and ambipolar behavior. First-principles calculations of the DOS of ZnCoO:H were in good agreement with the proposed DOS representation. Through a comparison of first-principles calculations and experimental data, evidence for the existence of Co–H–Co in ZnCoO:H is suggested.

Ambipolar behavior in a hydrogenated Zn_0.8Co_0.2O (ZnCoO:H) film is investigated via resistivity and magnetoresistance measurements and first-principles calculations of the DOS. Evidence for the existence of Co–H–Co in ZnCoO:H is suggested.     

Electronic and optical properties of Janus ZrSSe by density functional theory

In the present work, we investigate systematically the electronic and optical properties of Janus ZrSSe using first-principles calculations. Our calculations demonstrate that the Janus ZrSSe monolayer is an indirect semiconductor at equilibrium. The band gap of the Janus ZrSSe is 1.341 eV using the Heyd–Scuseria–Ernzerhof hybrid functional, larger than the band gap of ZrSe₂ monolayer and smaller than that of ZrS₂ monolayer. Based on the analysis of the band edge alignment, we confirm that the Janus ZrSSe monolayer possesses photocatalytic activities that can be used in water splitting applications. While strain engineering plays an important role in modulating the electronic properties and optical characteristics of the Janus ZrSSe monolayer, the influence of the external electric field on these properties is negligible. The biaxial strain, ε_b, has significantly changed the band of the Janus ZrSSe monolayer, and particularly, the semiconductor–metal phase transition which occurred at ε_b = 7%. The Janus ZrSSe monolayer can absorb light in both visible and ultraviolet regions. Also, the biaxial strain has shifted the first optical gap of the Janus ZrSSe monolayer. Our findings provide additional information for the prospect of applying the Janus ZrSSe monolayer in nanoelectronic devices, especially in water splitting technology.

In the present work, we investigate systematically the electronic and optical properties of Janus ZrSSe using first-principles calculations.     

First-principles study of vanadium carbides as electrocatalysts for hydrogen and oxygen evolution reactions

Vanadium carbides have attracted much attention as highly active catalysts in both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), while a satisfactory understanding of the underlying mechanisms still remains a challenge. Herein we apply first-principles calculations to systematically analyze the crystal structures, electronic properties, free energies during the HER and OER processes, surface energies and crystal formation energies of the three types of vanadium carbides, i.e., V₄C₃, V₈C₇ and VC. We show that all these vanadium carbides are metallic, which enables efficient electron transport from the bulk to the surface of the catalysts. All these vanadium carbides exhibit excellent HER performance but show poor OER catalytic activity. In particular, the V₈C₇ (110) surface shows the best catalytic performance for its relatively small |ΔG(H*)| value (−0.114 eV) for HER. Emergence of natural carbon vacancies gives rise to large surface energy, proper hydrogen adsorption energy, low crystal formation energy and weak bond strength in V₈V₇, which guarantees its leading position among the three vanadium carbides. In addition, a remarkable resemblance between VC/V₈C₇ and Pt in their electronic structures on (110) and (111) surfaces are found, which indicates a Pt-like HER mechanism in these vanadium carbides. Our results thus bring new insights to the theoretical understanding of the excellent HER performance of vanadium carbides.

The origin of excellent performance of vanadium carbides (VC and V₈V₇) in hydrogen and oxygen evolution reactions (HER and OER) is revealed by first-principles calculations. It is found that the underlying mechanisms in HER/OER processes are Pt-like.     

First-principles prediction of chemically functionalized InN monolayers: electronic and optical properties

In this work, we consider the electronic and optical properties of chemically functionalized InN monolayers with F and Cl atoms (i.e., F–InN–F, F–InN–Cl, Cl–InN–F, Cl–InN–Cl monolayers) using first-principles calculations. The adsorption of the F and Cl atoms on the InN monolayer is determined to be chemically stable and the F–InN–F monolayer is most likely to occur. Our calculations show that the chemical functionalization with Cl and F atoms not only breaks the planar structure of InN monolayer but also increases its band gap. By using both Perdew, Burke, and Ernzerhof (PBE) and the Heyd–Scuseria–Ernzerhof (HSE06) hybrid functionals, all four models of chemically functionalized InN monolayers are found to be semiconductors with direct energy gaps and these gaps depend on the constituent species. When the spin–orbit coupling (SOC) was included, the energy gap of these monolayers was reduced and an energy splitting was found at the Γ-point in the valence band. Chemically functionalized InN monolayers can absorb light in a wide region, especially the F–InN–F and Cl–InN–F monolayers have a strong ability to absorb the visible light. Our findings reveal that the chemically functionalized InN monolayers have potential applications in next-generation optoelectronic devices.

In this work, we consider the electronic and optical properties of chemically functionalized InN monolayers with F and Cl atoms (i.e., F–InN–F, F–InN–Cl, Cl–InN–F, Cl–InN–Cl monolayers) using first-principles calculations.     

Effect of vacancies on the structural and electronic properties of Ti2CO2

Ti₂CO₂ MXene is widely considered as a potential candidate material for sensors and optical devices. In this paper, first-principles calculations are performed to investigate the structural and electronic properties of pristine and vacancy defect Ti₂CO₂ monolayer. The results indicate that C-vacancy is energetically more favorable than Ti-vacancy and O-vacancy because of the smaller formation energy of C vacancy. The introduction of vacancy defects results in the transition from semiconductor to metal, and improves the electronic conductivities of Ti₂CO₂ monolayer. The introduction of C and O vacancies causes the Ti-d state to split into several peaks in the energy range of 0 to 2 eV, while the introduction of Ti vacancy makes the Ti-d state weaker and the C-p state stronger. Furthermore, the work function can be effectively engineered by vacancy defects.

Ti₂CO₂ MXene is widely considered as a potential candidate material for sensors and optical devices.     

Electronic and transport properties of zigzag phosphorene nanoribbons with nonmetallic atom terminations

Using the first-principles method based on density-functional theory and nonequilibrium Green''s function, electronic properties of zigzag phosphorene nanoribbons (ZPNRs) terminated with nonmetallic (NM) atoms such as H, C, F, N, O, S and Si, as well as a pristine case, are studied systematically. Three possible cases are considered, namely, ZPNRs with symmetrical edge terminations, asymmetrical edge terminations, and the half-bare edge case. It is shown that the pristine ZPNRs show metallic behavior. For ZPNRs terminated with C, O, S and Si atoms, they are always metals regardless of the termination cases. For ZPNR terminated with H, F, and N, the electronic structure is either a metal or a semiconductor, which depends on the termination cases. The results from the calculated edge formation energy show that the ribbons with C, F, N, O, S and Si atom edge modifications are more stable than the H-terminated ZPNR. Moreover, an applied external transverse electric field can effectively modulate the bandgaps of ZPNRs terminated with H, F and N, especially reducing the gap with the increase of the applied external transverse electric field strength. The ZPNRs terminated with N undergo a semiconductor-to-metal transition. We also investigate the electronic transport properties in nano devices consisting of the ZPNRs terminated respectively by O and S at both edges and with the fully bare edge. It is found that O and S terminated ZPNR devices have a good linear response on bias, and the current is bigger than the pristine case. The results indicate that the introduction of NM atoms at the edge(s) can effectively modulate the electronic and transport properties of ZPNRs. These novel electronic properties suggest that PNRs are a promising candidate for future nanoelectronic and optoelectronic applications.

Using the first-principles method based on density-functional theory and non-equilibrium Green''s function, the electronic properties of zigzag ZPNRs terminated with NM atoms, as well as a pristine case, were studied systematically.     

Effect of Zn doping on phase transition and electronic structures of Heusler-type Pd2Cr-based alloys: from normal to all-d-metal Heusler

Based on first-principles calculations, for Heusler alloys Pd₂CrZ (Z = Al, Ga, In, Tl, Si, Sn, P, As, Sb, Bi, Se, Te, Zn), the effect of Zn doping on their phase transition and electronic structure has been studied in this work. These alloys can be divided into two classes: (i) all-d-metal Heusler Pd₂CrZn and (ii) other normal Heusler alloys Pd₂CrZ (Z = Al, Ga, In, Tl, Si, Sn, P, As, Sb, Bi, Se, Te). For all-d-metal Heusler alloy Pd₂CrZn, transition metal element Zn behaves like a main group element due to its full 3d occupied state, and therefore the Zn atoms tend to occupy Wyckoff sites D (0.75, 0.75, 0.75) instead of replacing Pd atoms at A sites (0, 0, 0). The stable tetragonal L1₀ state is obtained via tetragonal deformation and the L1₀ stable state can be tuned by the uniform strain. The stability of the tetragonal state is analyzed and proved via calculation of the density of states (DOSs) and the phonon spectrum. For the series of normal Heusler alloys Pd₂CrZ, doping with Zn atoms can induce or strengthen the martensitic transformation, or regulate the large c/a ratios to a more reasonable range. It is hoped that this work can provide some guidance for further studies of the relationship between all-d-metal and normal Heusler alloys in the future.

By first-principles calculations, for Heusler alloys Pd₂CrZ (Z = Al, Ga, In, Tl, Si, Sn, P, As, Sb, Bi, Se, Te, Zn), the effect of Zn doping on their phase transition and electronic structure has been studied in this work.     

Investigation of strain and doping on the electronic properties of single layers of C6N6 and C6N8: a first principles study

In this work, by performing first-principles calculations, we explore the effects of various atom impurities on the electronic and magnetic properties of single layers of C₆N₆ and C₆N₈. Our results indicate that atom doping may significantly modify the electronic properties. Surprisingly, doping Cr into a holey site of C₆N₆ monolayer was found to exhibit a narrow band gap of 125 meV upon compression strain, considering the spin–orbit coupling effect. Also, a C atom doped in C₆N₈ monolayer shows semi-metal nature under compression strains larger than −2%. Our results propose that Mg or Ca doped into strained C₆N₆ may exhibit small band gaps in the range of 10–30 meV. In addition, a magnetic-to-nonmagnetic phase transition can occur under large tensile strains in the Ca doped C₆N₈ monolayer. Our results highlight the electronic properties and magnetism of C₆N₆ and C₆N₈ monolayers. Our results show that the electronic properties can be effectively modified by atom doping and mechanical strain, thereby offering new possibilities to tailor the electronic and magnetic properties of C₆N₆ and C₆N₈ carbon nitride monolayers.

Using first-principles calculations, we explore the effects of atom doping and strain on the structural, electronic, and magnetic properties of C₆N₆ and C₆N₈ monolayers.     

Abundant topological phases in hydrogenated group-IV binary alloy compounds

Based on the widely studied two-dimensional layered materials, new materials with unique properties can be acquired by stacking the layered materials with different styles. By using density-functional calculations and symmetry analysis, we here present a route to produce abundant topologically nontrivial electronic states in three-dimensional compounds made of stacked monolayer hydrogenated group-IV binary alloys. Triply degenerate point (TDP) semimetals and Dirac semimetals are found in the hydrogenated SnPb compounds with different stacking configurations. The TDP semimetal is characterized by two sets of near-Dirac TDPs, stemming from the inversion of the s (p_z) and p_x,y bands from the Pb (and also Sn) atoms and protected by a C_3v double point group symmetry. Type-I and type-II states, and one essential Dirac semimetal state, coexist in a hydrogenated SnPb compound. Hourglass surface states are also observed in this case. For the hydrogenated GeSn and GePb compounds, normal insulators and weak topological insulators (and also Dirac semimetals) are obtained, respectively. The topological nature of the states is identified by calculations of topological indexes as well as surface states. With these extremely rich topological phases, the studied compounds offer an ideal material platform for realizing topological semimetals and insulators in experiments.

Abundant topological states, including triply degenerate point semimetals and Dirac semimetals, are achieved in the layered SnPbH₂ crystals built based on monolayer SnPbH₂ with different stacking patterns.     

Strain-tunable electronic and optical properties of BC3 monolayer

Two-dimensional layered nanostructures with unique electronic and optical properties may hold great potential in nanoelectronics and optoelectronics applications. In this work, structural stability, elastic, electronic, and optical properties of BC₃ monolayers have been investigated using a first-principles study. The BC₃ monolayer can be regarded as a series of hexagonal C rings with the connections of B atoms, which has been tested to be highly dynamically stable. The in-plane stiffness is 316.2 N cm⁻¹, potentially rivalling graphene. A screened hybrid density functional HSE06 is used to calculate the electronic and optical properties. It is found that the BC₃ monolayer is an indirect band gap semiconductor with a moderate gap energy of 1.839 eV. Spatial charge distribution to the valence band maximum and the conduction band minimum is analyzed to explore the origin of indirect band gap features. By calculating the complex dielectric function, optical properties considered as excitonic effects are discussed. Besides, the effects of various in-plane strains on electronic and optical properties are explored. Our results of good structural stability, moderate and tunable band gap, and strain-controllable optical properties suggest that the BC₃ monolayer holds great promise in the applications of nanoelectronic and optoelectronic devices.

The BC₃ monolayer holds great promise in the applications of nanoelectronic and optoelectronic devices due to its good structural stability, moderate and tunable band gap, and strain-controllable optical properties.     

Insight into the electronic and thermodynamic properties of NbSi2 from first-principles calculations

The electronic and thermodynamic properties of NbSi₂ with four structures (C40, C11_b, C54 and C49) were studied in terms of first-principle calculations. The band structure and density of states of four NbSi₂ are calculated. Those disilicides show electronic properties because the band gap between the conduction band and the valence band is near the Fermi level. Their metallic character is mainly due to the strong metallic interaction between the Nb-4d state and Si-3p state. The formed Si–Si covalent bond is mainly concentrated in the valence band. The valence electron configuration of Nb–Si and Si–Si bonds is also explored. Besides, we study the thermodynamic properties of NbSi₂ as a function of temperature. The results indicate that the C54 structure has the best thermal stability in the obtained phases. In particular, the Debye temperature and heat capacity of the C54 structure are 547.8 K and 142.7 J mol⁻¹ K⁻¹, respectively. The calculated phonon DOS provides the explanation that the nature of the thermodynamic properties is mainly derived from the vibration of Si atoms.

The electronic and thermodynamic properties of NbSi₂ with four structures (C40, C11_b, C54 and C49) were studied in terms of first-principle calculations.     

Epitaxial growth and interfacial property of monolayer MoS2 on gallium nitride

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) on semiconductor substrates are important for next-generation electronics and optoelectronics. In this study, we demonstrate the growth of monolayer MoS₂ on a lattice-matched gallium nitride (GaN) semiconductor substrate by chemical vapor deposition (CVD). The monolayer MoS₂ triangles exhibit optical properties similar to that of typical single-crystal MoS₂ sheets, as verified by the Raman, photoluminescence, and morphological characterizations. The Raman and PL features and their intensity mappings suggest that the as-grown MoS₂ on GaN substrate can achieve high quality and uniformity, demonstrating that GaN substrate is favorable for 2D MoS₂ growth. Moreover, the interfacial property and stacking structure were investigated by first-principles density functional theory (DFT) calculations to confirm the interlayer interactions of monolayer MoS₂ on GaN. Accordingly, the ability to grow high quality monolayer MoS₂ on semiconductor GaN substrate would open a new route toward the synthesis of hetero and composite structures for promising electronic and optoelectronic device applications.

Monolayer MoS₂ were grown on GaN substrate by CVD method, and the interfacial property of the MoS₂–GaN system were studied by first-principles density functional theory calculations.     

Exploring a silicene monolayer as a promising sensor platform to detect and capture NO and CO gas

Searching for new two-dimensional (2D) materials for the early and efficient detection and capture of toxic gas has received special attention from researchers. In this work, we investigate the adsorption of NO and CO molecules onto a silicene monolayer using first-principles calculations. Different numbers of adsorbates, as well as adsorption configurations, have been considered. The results show that up to four NO molecules can be chemically adsorbed onto the pristine monolayer with adsorption energies varying between −0.32 and −1.22 eV per molecule. In these cases, the gas adsorption induces feature-rich electronic behaviors, including magnetic semiconducting and half-metallicity, where the magnetic properties are produced mainly by the adsorbates. Except for two CO molecules adsorbing onto two adjacent Si atoms with an adsorption energy of −0.26 eV per molecule, other adsorption configurations show weak physisorption of CO molecules onto the pristine silicene platform. However, the sensitivity can be enhanced considerably by doping with Al atoms, drastically reducing the adsorption energy to between −0.19 and −0.71 eV per molecule. The doping and adsorption process may lead to either band gap opening or metallization, depending on its configuration. This study reveals the promising applicability of pristine and Al doped silicene monolayers as sensors for more than one single NO and CO molecule.

Magnetic and electronic properties of the NO-adsorbed silicene monolayer have been investigated.     

The effect of oxidation on the electronic properties of penta-graphene: first-principles calculation

Herein, using first-principles calculations, we systematically studied the effect of oxidation on the structural and electronic properties of penta-graphene. We have found that the oxygen atom prefers to adsorb at the center of the C C bond, and the interaction between the oxygen atom and penta-graphene is a strong chemical bond. When the oxygen coverage increases, the band gap of penta-graphene gradually widens due to the rigid up-shift of the conduction band. More importantly, we found that the oxygen molecule on the penta-graphene surface could self-decompose into oxygen atoms without any metal catalyst. Our calculated results show that penta-graphene would be chemically unstable when it is exposed to air. Therefore, from the application point of view, penta-graphene-based devices must be encapsulated or functionalized before exposure to air. Oxidized penta-graphene exhibits a large band gap, which can facilitate its application as dielectric layers in electronic devices.

Herein, using first-principles calculations, we systematically studied the effect of oxidation on the structural and electronic properties of penta-graphene.