Carbon nanotubes growth on sub-surface catalyst layer of Cu–Ni nanoparticles thin film

Cu–Ni nanoparticles (NPs) thin films were prepared by Direct Current (DC) magnetron sputtering with Cu and Ni targets. The products were used as catalysts for Thermal CVD (TCVD) growing of carbon nanotubes (CNTs) from acetylene gas at 825°C. In order to characterize the nano catalysts, X-ray Diffraction (XRD) and Atomic Force Microscopy (AFM) and to study the synthesized CNTs Scanning Electron Microscopy (SEM) and Raman Spectroscopy were applied. A remarkable CNT grown on the sub-surface of catalyst layer compared to its top is deduced from SEM images. Despite the poor catalytic activity of the top-surface, these considerations led us to conclude more catalytic activity of the sub-surface.     

Thermodynamic Phase Diagram,Half-Metallic and Optical Properties of the Zr2TiSi [111] Films Based on DFT

Silicon - Thermodynamic stability, electronic and optical properties of the Zr2TiSi compound in the bulk and its [111] films have been investigated, based on the density functional theory (DFT)...     

Study of Pressure Effects on the Elastic Stability and Optical Treatment of Co<Subscript>2</Subscript>VAl using GGA+U

First-principles calculations of the elastic and optical properties of Co₂VAl compound under pressure are performed in the framework of density functional theory. Applying pressure causes elastic stability, hardness, Young’s modulus and Shear modulus and Debye temperature. Also, Co₂VAl shows higher ductility and anisotropy under stress. Using GGA + U method, it is found that Co₂VAl has 100 % spin polarization at the Fermi level and its spin flip gap is increased by applying pressure. The Co₂VAl response to incident light is positive only in the visible area for all pressures, and its peak is shifted to higher energies under pressure. Also, in the visible range, a peak is observed for absorption and conduction which is increased by applying pressure.     

Prevailing Cu-C Nanocomposite over Cu NPs for CNTs Growth: A Catalyst Study on Silicon Substrate

Silicon - Copper nanoparticles in carbon thin films (Cu NPs @ a-C: H) were prepared with various copper and carbon content by co-deposition of RF-sputtering and RF-PECVD method to use as catalysts...     

Effect of Si and Ge Surface Doping on the Be<Subscript>2</Subscript>C Monolayer: Case Study on Electrical and Optical Properties

The electronic and optical properties of X (Si, Ge) doped Be₂C monolayer has been investigated using the all-electron full potential linear augmented plane wave (FP-LAPW + lo) method in a scalar relativistic version as embodied in the Wien2k code based on the density functional theory. Using cohesive energy calculation, it has been shown that the Si and Ge doped to Be₂C monolayer have stable structures and the doping processes modified the direct band gaps. The calculated electronic band structure confirm the direct band gap nature since the conduction band minimum and the valence band maximum are located at the center of the Brillouin zone. The total and partial density of states help to gain further information regarding the hybridizations and the orbitals which control the energy band gap. The calculated optical properties help to gain deep insight into the electronic structure. Our calculated results indicate that the X (Si, Ge) doped Be₂C monolayer can be have potential application in optoelectronics devices.     

Nickel Nanoparticle Catalyzed Growth of Multiwall CNTs on Copper thin Films Substrate

Protection of Metals and Physical Chemistry of Surfaces - Significant applications of metallic nanocatalysts motivated us to study the role of catalyst contents by choosing Cu–Ni nanocatalyst...     

Elastic and optical properties of zinc-blende CrSb and its effective mass

The elastic, optical, and effective mass properties of CrSb in zinc-blende（ZB） phase were investigated.The calculations were carried out using the full-potential linearized augmented plane wave plus local orbital according to the density functional theory. The results of elastic calculations by generalized gradient approximation and local density approximation approximations indicate that ZB CrSb is a ductile material and its Debye temperature is rather low. Band structure and density of state calculations introduce the ZB CrSb as a half-metal with spin polarization of100 %. In metal state, 16 th and 17 th bands cut off the Fermi level. Calculations study the effective mass, Fermi velocity,and Fermi surface at 16 th and 17 th bands. In continue,optical quantities such as dielectric function, energy loss function, and optical conductivity were investigated.     

Structural,Half-Metallic,Optical, and Thermoelectric Study on the Zr2TiX (X = Al,Ga, Ge,Si) Heuslers: by DFT

Silicon - Based on the density functional theory (DFT) framework, the mechanical, half-metallic (HF), optical and thermoelectric properties of Zr2TiX (X = Al, Ga, Ge, Si) Heusler compounds are...