Ali, Essam E.Darwish, A. A. A.Sebak, M. A.El-Denglawey, A....
6页查看更多>>摘要：Safranin-T/p-Si heterostructure (HS) as a hybrid organic/inorganic HS was fabricated. Thermal evaporation was used to deposit Safranin-T films. The X-ray diffraction spectrum of Safranin-T shows a single peak around a diffraction angle of 31.70, which can be ascribed to the growth along the (3 2 4) plane. The crystallite size of the Safranin-T films is estimated as 31 nm. The electrical and photoelectrical features of the Safranin-T/p-Si HS are examined regarding the current-voltage measurements. The ideality factor was calculated as 2.09 and decreased with increased temperature, while the height of the barrier is increased from 0.76 to 1.01 eV. This conduct has been clarified due to the inhomogeneities of the barrier at the Safranin-T/p-Si interface. Under the light, the Safranin-T/p-Si HS demonstrates photoelectrical behavior. The photovoltaic parameters (the open-circuit voltage, short circuit current, and conversion efficiency) are evaluated as 0.39 V, 0.544 mA, and 2.76%, separately.
原文链接:
NSTL
Elsevier
Geetha, G. V.Sivakumar, R.Slimani, Y.Sanjeeviraja, C....
14页查看更多>>摘要：In the present study, the enhanced photocatalytic behaviour of La:ZnWO4 and Ce:ZnWO4 nanoparticles produced by a simple co-precipitation technique is reported. The X-ray diffraction study suggested that La and Ce ions are harmoniously incorporated into the Zn2+ sites or interstitial sites within the ZnWO4 lattice without altering the monoclinic wolframite phase. The field emission scanning electron microscopic study showed the formation of spherical particles and nanorod-like morphology for La:ZnWO4 and Ce:ZnWO4 samples. The shrinkage in optical band gap energy of La and Ce doped ZnWO4 nanoparticles was realized owing to the effect of dopant concentration induced microstructural defects. The broad blue-green emission peak perceived at 350-600 nm regions is ascribed to the electronic transition from O2p to W5d orbitals. The highest surface area of 283.272 m(2)/g was obtained for 2% La doped ZnWO4 sample. The elemental composition of samples was ascertained by x-ray photoelectron spectroscopic study. La:ZnWO4 and Ce:ZnWO4 nanophotocatalysts showed an excellent dye removal efficiency towards the degradation of methylene blue than the pure ZnWO4 catalyst. This may be due to the fact that the RE ions (La and Ce) endorse the separation of photo-induced electron-hole pairs in ZnWO4.
原文链接:- NSTL
- Elsevier
Patel, Shobhit K.Lavadiya, Sunil P.Parmar, JuveriyaAhmed, Kawsar...
8页查看更多>>摘要：The simple technique for achieving frequency reconfigurability is proposed using a single PIN diode. Biasing complexity is minimized by attaching the PIN diode at the top of the design. The presented design provides the directivity of 6.98 dB, minimum reflectance coefficient (S11) of -22.56 dB, normalized directivity of 88 degrees, and a total gain of 3.683 dB. The multiple bands of frequency tunability behaviour with the maximum frequency reconfigurability of 100 MHz. The location of the feed and slot of the patch is varied for locating the best performing points. The FR4 based lower profile dielectric helps cost reduction and mass production. The simulation is carried out using the HFSS simulator. The fabrication of the presented work is also included and compared with simulated results. The presented work is suitable for Wi-Max, 5G and WLAN applications.
原文链接:- NSTL
- Elsevier
Zhang, Jia-TaoRao, Si-SiZhang, DanZhang, Hai-Feng...
10页查看更多>>摘要：In this paper, the principle of the transfer matrix method (TMM) is applied to derive the dispersion relation of electromagnetic wave propagation in cylindrical photonic crystals (CPCs), and we further deduce the conditional equations for exciting the optical Tamm state (OTS) in the one-dimensional (1D) CPCs based on the excitation conditions for OTS in 1D photonic crystals. Both H-and E-polarization are involved. After that, four CPCs are designed with graphene as the main defect layer to verify the correctness of the formula, and the effects of different defect layer structures, dielectric thickness, chemical potential, and phenomenological scattering rate on the dispersion curve are discussed, separately. In contrast, differences due to defect layer structure and dielectric thickness are more easily to be observed. The chemical potential of graphene dependence on the k rho-omega curves is more likely to be a kind of positive correlation. While phenomenological scattering rate has the weakest effect on the results.
原文链接:- NSTL
- Elsevier
Rafee, VahdatRazeghizadeh, AlirezaGharaati, Abdolrasoul
5页查看更多>>摘要：The paper aims at providing new theoretical insights into geometrical and local field correction effects on the effective mass renormalization of interacting electrons in a two-dimensional electron gas, at finite temperature. For this purpose, the temperature-dependent dynamic dielectric function is studied within random phase approximation. Then, the short-range effects of exchange-correlation holes around electrons are employed in calculations through local field correction using Hubbard, finite-temperature Hubbard, and Singwi-Tosi-LandSjolander approximations. Finally, the effective mass renormalization is calculated utilizing the real part of the electron self-energy. The outcomes indicate that the effective mass renormalization is decreased with increasing of the thickness at all dimensionless electron densities within all approximations. Likewise, utilizing a local field correction will lead to reductions in effective mass renormalization at any temperature and dimensionless electron density.
原文链接:- NSTL
- Elsevier
Vaghela, M. V.Raval, DharaGajjar, P. N.Babariya, Bindiya...
8页查看更多>>摘要：The presented paper describes the structural, electronic, and optical properties of CuPt-L11 type structure of HgIn amalgam by means of first-principles calculations. The optimized structural parameters for rhombohedral CuPt-L11 type structures of HgIn were obtained using total energy minimization agree well with experimental results. The lowering of "s' orbital below "p' orbital in the electronic band structure with consideration of spin orbital interaction confirms the topological insulating behaviour of HgIn amalgam. The Lowdin charges, projected density of States (PDOS) and Fermi surfaces displayed the dominance of Hg "d' electrons mainly in the core region and "s', "p', "d' orbital hybridization in Hg and In atoms. The optical properties such as refractive index, extinction coefficient, electronic energy loss function (EELF), reflectivity and transmittance and absorption coefficient were computed with respect to the photon energy (eV). The evaluated refractive index n(omega) maximizes in the UV region. Moreover, maximum absorption has been observed at 1.90eV in the absorption spectra, which makes CuPt-L11 HgIn amalgam as promising material for near-infrared optoelectronic applications.
原文链接:- NSTL
- Elsevier
Kanyinda-Malu, C.Santiuste, J. E. Munozde la Cruz, R. M.
7页查看更多>>摘要：We report the effects of radius-, length-and pitch-sizes on the optical reflectance of a periodic square array of GaAs nanowires embedded in epoxy. The simulated system is a multilayer array constituted by alternating layers of epoxy and an effective medium of GaAs nanowires embedded in epoxy. For both s-and p-polarizations, we observe an oscillating behavior in the reflectance spectra, as a consequence of interferences in periodical systems. We found that the radius-and pitch-sizes significantly affect the reflectance of GaAs nanowires array, while the length-sizes do not present evidence of changes in the optical reflectance. For higher radius, the number of oscillations increases and consequently, the peak-to-peak distance decreases. Besides, there is a red-shift of the reflectance for increasing radius. For higher pitch, the number of oscillations also increases, and a red-shift is observed. We obtain dependence laws for the peak-to-peak distance and red-shift versus radius and versus pitch. These dependences obey approximate quadratic relations. Attending to the reflectance dependence on the light incidence angle, we have found that for s-polarized light, the reflectance is higher with increasing angles, in comparison to p-polarized light cases, independently of the radius and pitch values. For both polarizations, we found that the reflectance is increasing for greater radii and smaller pitches, independently of the incident angle.
原文链接:- NSTL
- Elsevier
Dehkordi, Nooshin HeydarianAlamdari, SanazRaeisi, Morteza
10页查看更多>>摘要：Ag+, Gd+3-doped CdWO4 (co-doped CWO) phosphor nanopowders were synthesized by an eco-friendly method and then embedded into the polymer matrix to produce a flexible and transparent thin film. A novel phosphor for the excitation by an ultraviolet source, 980 nm diode laser, and proton radiation was reported at room temperature and crystal structure, luminescent properties, and energy transfer between Ag+ and Gd+3 ions were thoroughly investigated. Elemental composition and chemical state analyses were measured using X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy studies. Crystal structure and phase identification were confirmed using powder X-ray diffraction measurement. Based on all results, the flexible phosphor film prepared has good thermal stability and efficient blue-green emission under UV light, laser, and proton excitation used in emissive displays applications.
原文链接:- NSTL
- Elsevier
Zeng, LiZhang, DanZhang, HaifengDong, Hanqing...
9页查看更多>>摘要：In recent years, electromagnetically induced absorption (EIA) has had potential application value in nonlinear optics and other fields, which attracts more and more attention. Based on the bright-dark-quasi-dark theory, an electromagnetically induced transparency (EIT) metamaterial is proposed which realizes the transition from EIT to EIA by adjusting the coupling distance. At the same time, a substantial enhancement in absorption has been achieved by adding four nested split-ring resonators (SRRs) as the quasi dark modes which are obtained by rotating the first nested split resonator 90 degrees in turn, and the absorption peak can reach 0.8969 at 0.412 THz. The study proves that the inter-layer coupling causes magnetic resonances which could lead to enhanced absorption. The structure also has polarization-insensitive characteristics. The influences of different structural parameters on absorption performance are further discussed in this paper. This absorption enhancement method has universal applicability and has huge potential application value in many fields such as optical signal processing, optical storage, quantum switching, and optical sensing, which also can be extended to microwave and infrared bands.
原文链接:- NSTL
- Elsevier
