Vanadium impurity effects on optical properties of Ti3N2 mono-layer: An ab-initio study

The present work is investigated the effect of vanadium impurity on electronic and optical properties of Ti3N2 monolayer by using density function theory (DFT) implemented in Wien2k code. In order to study optical properties in two polarization directions of photons, namely E||x and E||z, dielectric function, absorption coefficient, optical conductivity, refraction index, extinction index, reflectivity, and energy loss function of Ti3N2 and Ti3N2-V monolayer have been evaluated within GGA (PBE) approximation. Although, Ti3N2 monolayer is a good infrared reflector and can be used as an infrared mirror, introducing V atom in the infrared area will decrease optical conductivity because optical conductivity of a pure form of a material is higher than its doped form. Keywords: Dielectric function, Optical conductivity, DFT, Ti3N2: V mono-laye

Diamond nanocrystal thin films : case study on surface texture and power spectral density properties

Analyzing diamond nanocrystal (DNC) thin film morphology produced by the HFCVD technique is the main objective of the present work. Stereometric analysis of three-dimensional surface microtextures was carried out based on data obtained through atomic force microscopy (AFM), while the ISO 25178-2:2012 standard was applied to characterize surface topography. The Abbott–Firestone curve, peak count histograms, and Cartesian graphs, which were extracted through AFM images, gave valuable statistical information. As can be seen, the most isotropic sample was the Au catalyst (etched) deposited by the hot filament chemical vapor deposition method. Moreover, by increasing the time of DNC growth from 15 min to 60 min, the surface roughness was increased. In addition, the average power spectral density was calculated and furrows were determined for all samples.https://aip.scitation.org/journal/advhj2020Physic

Characterization of microroughness parameters in Cu-C nanocomposite prepared by co-deposition of RF-sputtering and RF-PECVD

The morphological parameter of a thin film surface can be characterized by power spectral density (PSD) function which provides a better description on topography rather than the root mean square (RMS) and super structure contributions. Through the present study, nanoparticle copper-carbon composite films were prepared by co-deposition of RF-sputtering and RF-PECVD method using acetylene gas and copper target. These films’ surface roughnesses were determined by using an atomic force microscope (AFM). The carbon content of the films was obtained by Rutherford back scattering (RBS) which was varied from 5% to 73%. The power values of PSD for the AFM data were determined by the fast Fourier transform (FFT) algorithms. The effect of carbon on the surface roughness of thin films was investigated. Changes in the relationship between the resistivity and fractal dimension were observed for investigating films

Surface micromorphology characterization of PDI8-CN2 thin films on H-Si by AFM analysis

A nanoscale investigation of three-dimensional (3-D) surface micromorphology of archetypical N, N0- bis (n-etyl) x:y, dicyanoperylene- 3, 4:9, 10 bis (dicarboximide) (PDI8-CN2) thin films on H-Si substrates, which are applicable in n-type semiconducting compounds, has been performed by using fractal analysis. In addition, surface texture characteristics of the PDI8-CN2 thin films have been characterized by using atomic force microscopy (AFM) operated in tapping-mode in the air. These analyses revealed that all samples can be described well as fractal structures at nanometer scale and their three dimensional surface texture could be implemented in both graphical models and computer simulations

Effect of point defects on the electronic density states of SnC nanosheets: First-principles calculations

In this work, we investigated the electronic and structural properties of various defects including single Sn and C vacancies, double vacancy of the Sn and C atoms, anti-sites, position exchange and the Stone–Wales (SW) defects in SnC nanosheets by using density-functional theory (DFT). We found that various vacancy defects in the SnC monolayer can change the electronic and structural properties. Our results show that the SnC is an indirect band gap compound, with the band gap of 2.10 eV. The system turns into metal for both structure of the single Sn and C vacancies. However, for the double vacancy contained Sn and C atoms, the structure remains semiconductor with the direct band gap of 0.37 eV at the G point. We also found that for anti-site defects, the structure remains semiconductor and for the exchange defect, the structure becomes indirect semiconductor with the K-G point and the band gap of 0.74 eV. Finally, the structure of SW defect remains semiconductor with the direct band gap at K point with band gap of 0.54 eV. Keywords: SnC nanosheets, Density-functional theory, First-principles calculations, Electronic density of states, Band ga