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(Bz) <sub/><i>n</i> </sub> and (VBz) <sub/><i>n</i> </sub> covalent functionalized MoS <sub/>2</sub> monolayer: electronic and transport properties
摘要： Inspired by Benzene (Bz) derivatives dramatically enhancing MoS2 monolayer electronic properties (ACS Nano. 2015, 9, 6018–6030), we have investigated electronic and transport properties of (Bz)n/MoS2 and (VBz)n/MoS2, which are designed by grafting (Bz)n and (VBz)n arrays onto 2D monolayer MoS2 (ML-MoS2), respectively, using density functional theory (DFT) and non-equilibrium Green’s function (NEGF) methods. ML-MoS2 provides a perfect substrate for grafting (Bz)n and (VBz)n arrays upon its surface as a result of stable covalent binding energy with -3.841 eV and -1.953 eV for (Bz)n/MoS2 and (VBz)n/MoS2 respectively. From the electronic properties, we can find that grafting (Bz)n onto the ML-MoS2 surface turns ML-MoS2 from typical semiconductor to metallic properties because four wide bands coupled by (Bz)n and MoS2 in (Bz)n/MoS2 show better delocalization in heterointerface, resulting to these bands across the Fermi level (Ef). Furthermore, the introduction of metal V. Transport properties of ML-MoS2, (Bz)n/MoS2 or (VBz)n/MoS2 for two-probe devices are all studied in zigzag and armchair direction. The ferromagnetic (VBz)n/MoS2 shows a spin polarized transport characteristic, spin-down state gives a higher conductivity than spin-up state. By comparison the zigzag direction is the preferential pathway for electron transport. Finally this work suggests that the novel (VBz)n nanowire grafted on MoS2 should have potential application in low-dimensional magnetic nanoelectronic devices.
关键词： (Bz)n/MoS2,(VBz)n/MoS2,covalent functionalized,electronic property,transport property
更新于2025-09-23 15:22:29
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Structural, electronic and optical properties of InAs phases: by GGA-PBG and GGA-EV approximations
摘要： Structural, electronic and optical properties of InAs are investigated in the zinc-blende (ZB), rock-salt (RS) and wurtzite (WZ) phases using the full potential linearised augmented plane wave method in the framework of density functional theory (DFT). The electronic band gap of the ZB and WZ phases are improved and in good agreement with experiments by GGA-EV approximation. This compound has a direct band gap in the ZB and WZ phases in Γ point at the centre Brillouin zone and in the RS phase the conduction band crosses towards the valence band and has metallic behaviour. Also, the optical parameters such as the real and imaginary parts of epsilon, energy loss, and the refraction and reflection indices of all the phases are calculated and compared. The calculated optical properties of InAs have promising applications such as the design of optoelectronic and photonic devices.
关键词： density functional theory,optical property,GGA-EV,electronic property,InAs
更新于2025-09-23 15:22:29
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Investigation of the structural and electronic properties of InP1-xSbx alloy for mid-infrared optoelectronic applications: A TB-mBJ DFT study
摘要： The structural and electronic properties of InP1(cid:1)xSbx supercell structure at different percent of Sb incorporation have been studied under the Density Functional Theory formalism employing WIEN2K package. From the total energy calculations, the supercell lattice structures have been optimized. The structural properties have been calculated from the equation of state which suggests the supercell structures to be signi?cantly stable with a higher degree of compressive ?exibility (speci?cally, at lower percent of Sb incorporation). The contribution of the partial and total DOS (Density of States) of constituent elements to total DOS of the supercell structure has been investigated. The relativistic effects have been assimilated into the band structure calculation, along various high symmetry k directions for each supercell structure. The values obtained for band gap (both, direct and indirect), spin-orbit splitting energy and bowing coef?cient have been observed to vary signi?cantly as a function of Sb mole fraction. Moreover, a relationship has been established between band gap (both, direct and indirect) values and spin-orbit splitting energy with Sb mole fraction. The in?uence of SOC (spin-orbit coupling) effect on the parameters concerning electronic properties has also been analyzed. The effective mass values for conduction and valence sub-bands (heavy hole, light hole and spin orbit split-off hole) near the Brillouin zone has been calculated at different percent of Sb incorporation in InP1(cid:1)xSbx supercell structure. The interpretation of these results obtained suggests InP1(cid:1)xSbx material to be competent for mid-infrared optoelectronic applications.
关键词： III-V semiconductor,Electronic band structure,DOS,DFT calculation,Effective mass calculation,Structural and electronic property
更新于2025-09-23 15:21:01
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Synthesis of nanosheet-assembled porous NiO/ZnO microflowers through a facile one-step hydrothermal approach
摘要： The unique flower-like NiO/ZnO composite with porous nanosheets has been triumphantly manufactured via the one-step hydrothermal method initially. On the basis of morphology observations and ethanol gas measurements, it is considered that the construction of P-N junctions at the interface as well as the sheet-like porous microflowers architecture greatly contribute to the fantastic gas sensing properties of the prepared materials, which exhibit superb gas response value and outstanding repeatability. Furthermore, a possible formation mechanism is proposed, elucidating the process of the oriented-attachment, the self-assembly in addition to the pores-development.
关键词： Semiconductor,NiO/ZnO,Porous microflower,Electronic property,Functional
更新于2025-09-19 17:13:59
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Influence of Pressure on the Mechanical and Electronic Properties of Wurtzite and Zinc-Blende GaN Crystals
摘要： The mechanical and electronic properties of two GaN crystals, wurtzite and zinc-blende GaN, under various hydrostatic pressures were investigated using first principles calculations. The results show that the lattice constants of the two GaN crystals calculated in this study are close to previous experimental results, and the two GaN crystals are stable under hydrostatic pressures up to 40 GPa. The pressure presents extremely similar trend effect on the volumes of unit cells and average Ga-N bond lengths of the two GaN crystals. The bulk modulus increases while the shear modulus decreases with the increase in pressure, resulting in the significant increase of the ratios of bulk moduli to shear moduli for the two GaN polycrystals. Different with the monotonic changes of bulk and shear moduli, the elastic moduli of the two GaN polycrystals may increase at first and then decrease with increasing pressure. The two GaN crystals are brittle materials at zero pressure, while they may exhibit ductile behaviour under high pressures. Moreover, the increase in pressure raises the elastic anisotropy of GaN crystals, and the anisotropy factors of the two GaN single crystals are quite different. Different with the obvious directional dependences of elastic modulus, shear modulus and Poisson’s ratio of the two GaN single crystals, there is no anisotropy for bulk modulus, especially for that of zinc-blende GaN. Furthermore, the band gaps of GaN crystals increase with increasing pressure, and zinc-blende GaN has a larger pressure coefficient. To further understand the pressure effect on the band gap, the band structure and density of states (DOSs) of GaN crystals were also analysed in this study.
关键词： first principle,electronic property,GaN,pressure,mechanical property
更新于2025-09-10 09:29:36
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Predicted semiconducting beryllium sulfides in 3D and 2D configurations: Insights from first-principles calculations
摘要： Light-metal sulfides have attracted great attention due to the technological application as energy storage devices. Combining first-principles calculations with structure searching, sulfur-rich compounds were explored theoretically in Be-S system. Interestingly, our results identify a hitherto unknown stoichiometry BeS2 in bulk and two-dimensional (2D) configuration. With the pressure increasing, BeS2 in bulk adopts P1(cid:2) structure at ambient pressure, C2 phase over 1.6GPa and then a cubic c-BeS2 with unique S2 2- dimmers up to 5.8GPa. The monolayer penta-BeS2 with Be2S3 pentagons and bilayer BeS structure are presented. Predicted c-BeS2, 2D BeS2 and BeS phases show a semiconducting character, interestingly, c-BeS2 is found to have a direct band gap of 1.52eV. The discovery of unknown beryllium sulfides and the understanding of electronic and chemical bonding properties will provide prerequisite for the potential application in electrochemistry.
关键词： Electronic property,First-principles calculations,Beryllium sulfides,Structural stability
更新于2025-09-10 09:29:36
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The stability and electronic properties of Si-doped ZnO nanosheet: A DFT study
摘要： This work deals with stability, structural and electronic properties of perfect ZnO nanosheet and substiutionally doped ZnO nanosheet with Si are simulated and optimized successfully using density functional theory (DFT) with the help of SIESTA program in the generalized gradient approximation (GGA). The substitution atoms have been replaced on the oxygen site in line and zigzag doping. The stability of perfect ZnO nanosheet and ground state structures of Sin-ZnO (n=1-6) are studied in terms of binding energy, show that a maximum stabilized of one Si in line doping and two Si in zigzag doping due to the dopant located in the center of nanosheet is a more stable. The electronic properties of ZnO nanosheet and Si-doped are discussed using ionization potential, electron affinity, HOMO–LUMO gap, electronegativity, and hardness. The results showed the presence of silicon atoms substitution expands the bond length with respect to perfect ZnO nanosheets. The obtained values of HOMO and LUMO are slightly different and this suggests that different of position dopant play significant roles on electronic properties and large electron affinity at four silicon atoms doped ZnO nanosheet in two cases that it improved the electron more accepting ability. The study of HOMO-LUMO gap reveals that the gap decreases with the increase in number of Si dopant atoms in ZnO nanosheet. These results global gave molecular electronics important electronic applications and help us to replace some oxygen atoms instead of silicon atoms in ZnO nanosheet.
关键词： ZnO nanosheet,Silicon-doping,Electronic property.,Line & zigzag doping
更新于2025-09-04 15:30:14