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Search Results: 1 - 10 of 13652 matches for " Electronic Properties "
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Structural and Electronic Properties of Impurities on Boron Nitride Nanotube  [PDF]
Gabrielle P. Soares, Silvete Guerini
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.28102
Abstract: The structural and electronic properties of molybdenum and magnesium substitution doping in (10,0) boron nitride nanotube (BNNT), are investigated through first-principle calculations. The electronic band structures results indicate that the molybdenum doped systems behave as n-type impurity. However, the magnesium doped systems behave as p-type impurity when magnesium replaces boron, and as a n-type impurity when the magnesium replaces nitrogen. The analysis of the energies formation shows that the molybdenum replacing a boron and nitrogen atoms are more favorable than the magnesium substitution in boron and nitrogen.
The Synthesis and Characterization of Arc Melted Fe1-xAlx Alloys  [PDF]
Sandeep Rajan, Rajni Shukla, Anil Kumar, Anupam Vyas, Ranjeet Kumar Brajpuriya
Journal of Applied Mathematics and Physics (JAMP) , 2013, DOI: 10.4236/jamp.2013.12002
Abstract:

The paper presents correlation study on a series of Fe1-xAlx alloy samples prepared by arc melting. All the samples show crystalline structure, irrespective of the Al content and are textured mainly along (110) direction. The particle size decreases rapidly with x particularly after x > 0.3. The corresponding magnetic measurements were obtained at room temperature using a VSM, with a maximum applied field of 14 kOe. The results show that the ferromagnetic state of the samples disappears with x, and becomes paramagnetic for alloys with x ≥ 0.4. It is also found that coercivity (Hc) and resistivity increase with x. The results were interpreted in terms of continuous change in their electronic structure i.e. overlap of the electron wave functions of the magnetic atoms with the Al electron wave function.

Quantum Chemical Studies of Endofullerenes (M@C60) Where M = H2O, Li+, Na+, K+, Be2+, Mg2+, and Ca2+  [PDF]
Osmair Vital de Oliveira, Arlan da Silva Gon?alves
Computational Chemistry (CC) , 2014, DOI: 10.4236/cc.2014.24007
Abstract: Quantum chemical calculations were performed to investigate the structural and electronic properties of seven endofullerenes. The interaction energies indicated that all of the chemical species are stable inside the fullerene for each complex. The ionization potential and electron affinity values suggest that the endofullerenes consisting of alkaline earth ions are the most reactive and that the dipole moment decreased according to the following order: Be2+@C60 (4.75) > Mg2+@C60 (3.14) > Ca2+@C60 (2.24) > Li+@C60 (1.26) > Na+@C60 (0.76) > H2O@C60 (0.24) > K+@C60 (0.00 Debye). These results imply that the solubility of endofullerenes in a polar solvent may increase from H2O@C60 to Be2+@C60. The energetic gaps indicate that Be2+@C60 and Mg2+@C60 possess a higher electrical conductivity, and the UV spectra show a shift in the bands to the visible light region. The results of this work may be useful for the development of new endofullerenes.
Conductive Behavior and Morphology of Axially Modified Gallium Phthalocyanine Thin Films onto Indium Tin Oxide Substrates  [PDF]
Margarita Rivera, Brenda Reyes, María Elena Sánchez-Vergara, Luis Humberto Mendoza-Huizar
Advances in Materials Physics and Chemistry (AMPC) , 2016, DOI: 10.4236/ampc.2016.67021
Abstract: Semiconductor molecular films based on a gallium phthalocyanine chloride (GaPcCl) and a bidentate amine were prepared by using vacuum thermal evaporation and electrochemical techniques in order to investigate the preferred conduction paths within the films. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) were employed to characterize the morphology of the films. The conductivity measurements were performed with two different methods in order to investigate preferential conduction directions. The film transverse conductivity was obtained by using scanning tunneling spectroscopy (STS) and the in-plane film conductivity was measured with a four-point probe system. From spectroscopy measurements, the tunneling conductance (dI/dV) was also obtained. From these results, it was found that the conductive nature of the films was strongly influenced by the deposition technique which in turn defined the morphological characteristics of the film. The evaporated method showed better conductivity response and provided semiconductor characteristics in the film transverse direction with an in-plane ohmic response. Finally, contact angle measurements were performed and showed hydrophobic characteristics in all cases.
Effect of Boron (Nitrogen)-Divacancy Complex Defects on the Electronic Properties of Graphene Nanoribbon  [PDF]
Zhiyong Wang, Junchao Jin, Mengyao Sun
Graphene (Graphene) , 2017, DOI: 10.4236/graphene.2017.61002
Abstract: We report the effect of boron (nitrogen)-divacancy complex defects on the electronic properties of graphene nanoribbon by means of density functional theory. It is found that the defective subbands appear in the conduction band and valence band in accordance with boron (nitrogen)-divacancy defect, respectively; the impurity subbands don’t lead to the transition from the metallic characteristic to a semiconducting one. These complex defects affect the electronic band structures around the Fermi level of the graphene nanoribbon; the charge densities of these configurations have also changed distinctly. It is hoped that the theoretical results are helpful in designing the electronic device.
First-Principle Studies on the Ga and As Doping of Germanane Monolayer  [PDF]
Lei Liu, Yanju Ji, Yifan Liu, Liqiang Liu
Journal of Applied Mathematics and Physics (JAMP) , 2019, DOI: 10.4236/jamp.2019.71005
Abstract: The study of energetics, structural, the electronic and optical properties of Ga and As atoms substituted for doped germanane monolayers were studied by first-principles calculations based on density functional theory. Both of the two doping are thermodynamically stable. According to the band structure and partial density of the states, gallium is p-type doping. Impurity bands below the conduction band lead the absorption spectrum moves in the infrared direction. Arsenic doping has impurity level passing through the Fermi level and is n-type doping. The analysis of optical properties confirms the value of bandgap and doping properties.
Electronic and Structural Properties of Li3AlP2 and Li3AlAs2 from First Principles  [PDF]
Mehrdad Dadsetani, Shirin Namjoo
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.29110
Abstract: A detailed analysis of the electronic and structural properties of the filled tetrahedral semiconductors Li3AlP2 and Li3AlAs2 has been performed, using the full potential linearized augmented plane wave method within the density functional theory. Experimental results about the structural properties, involves the positions of the elements Al and P(As). Since there were not any other efforts about the positions of the Li elements in these compounds, so to our knowledge there was no theoretical study about them till now. In the first step the interactional forces between atoms were minimized. The calculated internal coordinations of atoms agree well with the experimental results. Using these positions we obtained the equilibrium lattice constants, bulk modulus and their pressure derivative. In the second step the electronic properties of Li3AlP2 and Li3AlAs2 have been studied. The study of total and partial electronic DOS indicate the main contribution of DOS consists of P(As) 3p(4p) and P(As) 3s(4s) states. Our band structure calculation verifies that Li3AlP2 is an indirect gap semiconductor with a value of about 2.36 eV between valance band maximum occuring at H point and conduction band minimum occuring at Г point; though the difference between the direct (2.38 eV) and indirect (2.36 eV) is very small. We also found that Li3AlAs2 is a direct band gap (1.49 eV) in the center of BZ.
Morphology and Electronic Properties of Hybrid Organic-Inorganic System: Ag Nanoparticles Embedded into CuPc Matrix  [PDF]
I.M. Aristova, O.Yu. Vilkov, A. Pietzsch, M. Tchaplyguine, O.V. Molodtsova, V.Yu. Aristov
Advances in Materials Physics and Chemistry (AMPC) , 2012, DOI: 10.4236/ampc.2012.24B017
Abstract:

Materials with a high on-off resistance ratio could become the basis for resistive random-access memory (RRAM). It is assumed that one of RRAM types can be based on hybrid organic-inorganic systems, while particular attention is focused on hybrid systems consisting of metal nanoparticles (NP) embedded in organic matrix (OM). In this investigation we created and studied the hybrid organic-inorganic systems made of metal (Ag) nanoparticles embedded in organic semiconductor material CuPc. The LEED patterns and NEXAFS data demonstrate that the CuPc films deposited on Au(001) substrate are highly ordered and molecular planes lie parallel to the gold surface. The metal atoms were deposited on the outer surface of the organic molecular film and self-assembled into nanoparticles due to surface and bulk diffusion. The properties of nano-composite materials seem to be significantly dependent on the microstructure, i.e. the size, concentration, bulk- and size-distribution of nanoparticles; therefore we have studied by high resolution transmission electron microscopy the evolution of morphology of nano-composite films as a function of nominal metal deposition. The filled and empty electronic states of the hybrid organic-inorganic systems, energy level alignment at interfaces formed between metal nanoparticles and the organic semiconductor CuPc as well as the chemical interaction at the NP/OM interface were studied by UPS, XPS and NEXAFS methods.

 

Electronic and Optical Properties of Rocksalt CdO: A first-Principles Density-Functional Theory Study  [PDF]
Gang Yao, Xinyou An, Hongwen Lei, Yajun Fu, Weidong Wu
Modeling and Numerical Simulation of Material Science (MNSMS) , 2013, DOI: 10.4236/mnsms.2013.31B005
Abstract: The structural, electronic and optical properties of rocksalt CdO have been studied using the plane-wave-based pseudo-potential density functional theory within generalized gradient approximation. The calculated lattice parameters are in agreement with previous experimental work. The band structure, density of states, and Mulliken charge population are obtained, which indicates that rocksalt CdO having the properties of a halfmetal due to an indirect band gap of -0.51eV. The mechanical properties show that rocksalt CdO is mechanically stable, isotropic and malleable. Significantly, we propose a correct value for ε1(0) of about 4.75, which offers theoretical data for the design and application for rocksalt CdO in optoelectronic materials.
Theoretical Investigation of Electronic and Optical Properties of Si/SiGe Quantum Cascade Structures  [PDF]
Khadidja Zellat, Belabbes Soudini, Salah Mohamed Ait Cheikh
Advances in Materials Physics and Chemistry (AMPC) , 2013, DOI: 10.4236/ampc.2013.31004
Abstract:

This paper reviews the basic properties of the SiGe alloy, presents some new results on its electronic and optical properties, and discusses the approach that has been followed to model quantum wells containing SiGe layers for applications in quantum cascade lasers. The shape of the confining potential, the subband energies and their eigen envelope wave functions are calculated by solving a one-dimensional Schr?dinger equation. The calculations of optical parameters are used to optimize the Si/SiGe quantum cascade structures. Our results are found to be in good agreement with other calculations.

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