Segundo, Iran RochaAfonso, CatiaLima Jr, OrlandoCosta, Manuel F. M....
4页查看更多>>摘要：The determination of the band gap energy (E-g) of semiconductors powder materials can be performed from diffuse reflectance spectroscopy (DRS) measurements. For this purpose, the classical theory proposed by Kubelka and Munk (K-M) and the so-called plot Tauc, both discussed here, have been largely employed. We investigate the E-g values of anatase TiO(2 )particles synthesized by precipitation of titanyl sulphate in the presence of 5% ammonia solution and titanium and iron salts. Based on K-M function and Tauc plot and considering that the TiO2 anatase phase is an indirect band gap semiconductor, our results indicate that the samples subjected to a mechanochemical treatment (mill rotation speed equal to 300 rpm) present substantially lower E-g values compared to those reported by other authors in a recent work.
原文链接:
NSTL
Elsevier
Li, XuechaoChang, CengZhao, ZhuangDuan, Yiming...
5页查看更多>>摘要：We report the second harmonic generation (SHG) and third harmonic generation (THG) of GaAs/GaAlAs spherical quantum dots (QDs) with the modified Kratzer (MK) plus screened Coulomb (SC) potential in the presence of hydrostatic pressure and temperature. The eigen energies and wave functions can be deduced under the frame work of Nikiforov-Uvarov (NU) method. Then we calculate the SHG and THG coefficients within the framework of the density matrix method. Numerical calculations revealed that the SHG coefficient has two formants and THG coefficient has three formants depend on the energies and parameters of our system. The results indicate that these parameters bring about significant changes on the SHG and THG coefficients.
原文链接:- NSTL
- Elsevier
Jangid, P. K.Kumar, KishorArora, GunjanAhuja, B. L....
9页查看更多>>摘要：Electronic structure to judge trapping centres and activation energies in Mg-doped (2-8%) and Mg,Ti co-doped (2-3% each) LiF phosphors are presented using full-potential linearized APW method. Compton measurement for LiF is performed for appropriate choice of exchange-correlation potentials used in electronic properties. It is seen that 2-6% of Mg activator leads to formation of electronic traps with activation energy between 0.79 and 0.49 eV. At high concentration (>6%) of Mg, the formation of trap centres vanishes. Co-doping of 2% Mg,Ti permits the formation of trap centres, which is in contrast to higher concentrations. Mg-3s states play key role in the building of electronic trap centres. Higher concentration of Ti and Mg activators in LiF leads to the widening of 3d and 3s states, respectively. Analysis of optical response (frequency-dependent dielectric constants, trapping centres, and absorption coefficients) of 2% Mg-doped and 2% Mg,Ti co-doped LiF suggest their dosimetric applications and in ultra-violet detection.
原文链接:- NSTL
- Elsevier
Dheer, AshutoshKumar, Santosh
12页查看更多>>摘要：Chaotic mesoscopic cavities with ideal leads have been studied extensively using the powerful formalism of random matrix theory. Consequently, the statistical behavior of quantum transport observables, such as Landauer conductance and shot noise power, is fairly well understood. However, these have been explored far less in cavities with nonideal leads, i.e. having tunnel barriers. Here, we consider chaotic mesoscopic cavities with one ideal and one nonideal lead, and investigate the statistics of conductance and shot noise power under the condition of broken time-reversal symmetry. We derive exact expressions for the average and variance for both conductance and shot noise power. Moreover, we provide exact characteristic functions of these quantities, which are subsequently Fourier-inverted using a simple yet effective numerical procedure to obtain the corresponding distributions. We examine these quantities by varying the tunneling probabilities. We also compare our analytical results with Monte Carlo simulations and find very good agreements.
原文链接:- NSTL
- Elsevier
Outzourhit, A.Elmassi, S.Narjis, A.Nkhaili, L....
9页查看更多>>摘要：In this paper, Nickel oxide (NiO) thin films were synthesized by the reactive radio frequency sputtering. NiO thin films were annealed at different temperatures (350, 400, 450 and 500 C). Structural characterizations were performed using X-Ray Diffraction, Scanning Electron Microscopy (SEM), Raman spectroscopy, Infrared spectroscopy. Ultraviolet-visible spectrophotometer were used to estimate the energy band-gap and the thickness. Electrical resistivity measurements were carried out using the four-point probe method then analyzed basing on the structural characterization. The XRD patterns showed that the crystallite size increases by increasing the annealing temperature from 6.3 to 15.8 nm. The structure is cubic with lattice parameter of 4.17 nm and the dislocation and micro strain decrease by annealing. The Thin films surfaces were observed to be homogenous and without cracks. The Raman spectra proved the presence of four peaks, related to vibration of Ni-O bands. The FTIR spectra showed the NiO stretching and bending mode. The optical analyses showed that the transmittance and energy band gap augments by increasing the annealing temperature from 3.54 to 3.68 eV. Finally, the resistivity grows by annealing from 0.33 to 1.4 x 10(4) omega cm and decreases by increasing the measuring temperature.
原文链接:- NSTL
- Elsevier
Sahan, ZeynepAkkus, Uenal OzdenBerber, Savas
10页查看更多>>摘要：We have investigated TlGaS2 single-layer and TlGaS2 nanoribbons using density functional theory (DFT). Phonon dispersion curves calculated within the density functional perturbation theory indicate that the TlGaS2 single-layer is dynamically stable. Starting from optimized TlGaS2 single-layers, unterminated and terminated ribbon morphologies with varying edge Tl coverages were constructed. In order to account for the weak interaction between Tl and S atoms, van der Waals correction to DFT was employed. The electronic and magnetic structures of TlGaS2 ribbons are modulated by the edge morphology. Dangling bond, non-bonding, and free-electron-like edge states are formed. The ribbons have metallic conduction channels stemming from parabolic bands crossing the Fermi level. The edge states appearing in the fundamental energy gap induce spin polarization at the edges. The TlGaS2 nanoribbons provide two magnetic conduction channels along the Tl chains, and thus the nanoribbon acts as two magnetic nanowires.
原文链接:- NSTL
- Elsevier
Anlin, Lazar K.Vijoy, K. V.Pradeesh, K.Thomas, Shibi...
8页查看更多>>摘要：Energy harnessing gadgets which employ triboelectric effect have garnered global attention due to excellent output performance compared to other nanogenerators for various applications. In this article, an attempt has been made to modify the properties of poly dimethyl siloxane (PDMS), which is a tribo material by embedding it with metal nanoparticles of different conductivity and in different weight percent. TENGs based on metal nanoparticle/PDMS composite films are fabricated and electrical characteristics were examined. This study reveals that the filler with best conductivity exhibits excellent properties. Presence of silver nanoparticles increased the permittivity of the tribolayer from 5.3 to 16.9 for 20 wt% filler at 1 kHz. Electrical studies of silver/PDMS composite film gave appreciable results; 5.1 mu A (Isc), 33.6 V (Voc), 72.2 mu W power at 8 M omega with 10 N force at an excitation frequency of 10 Hz.
原文链接:- NSTL
- Elsevier
Gurgenc, EzgiDikici, AydinAslan, Fehmi
17页查看更多>>摘要：In the present study, different molar ratios of (1:0, 0:1, 3:1, 1:1, and 1:3) NiO:CdO composite thin films were coated on p-Si by a dynamic sol-gel spin coating method. Structural characterizations of NiO:CdO thin films were performed by XRD, FE-SEM, and EDX analysis. The photoresponse and electrical behavior of the fabricated photodiodes were determined by current-voltage (I-V), transient photocurrent-time (I-t), capacitance-voltage (C-V), conductivity-voltage (G-V), and transient photocapacitance-time (C-t) measurements. All fabricated photodiodes were exhibited rectifying properties and the photocurrent values increased as the light intensity was increased. All photodiodes are sensitive to light and it was determined that the NiO photodiode exhibited the highest photosensitivity value. Photocapacitance and photoconductance values of photodiodes were affected by light. Photoresponse and electrical behavior were affected by the interface states and the NiO:CdO ratio. The results show that Al/NiO:CdO/p-Si/Al photodiodes can be used as photosensors or photocapacitors in optoelectronic applications.
原文链接:- NSTL
- Elsevier
Ramanujam, N. R.Panda, AbinashYupapin, PreechaNatesan, Ayyanar...
10页查看更多>>摘要：The current work investigates the detection of a wide range of estradiol and progesterone hormone concentrations by the use of a defective 1D photonic crystal. The suggested structure consists of repeating layers of PbS and SiO2, with a central cavity layer. The transfer matrix technique is manipulated to examine the transmission spectrum of the proposed structure. The mainstay of the present work is to analyse the shift in the wavelength of the defect mode concerning the changes in different concentrations of hormones that are infiltrated into the cavity layer. In the course of a simulation, various geometrical parameters such as the thickness of the cavity layer and incident angle are properly optimized to envisage high performance. The colour map plot is investigated to convey a clear view of the shift of defect mode position concerning the change in incident angle. Moreover, all the sensing parameters like sensitivity, figure of merit, quality factor, signal-to-noise ratio, sensor resolution, and limit of detection are evaluated for each hormone at different incident angles. The main application behind this study is that it is important to sense the levels of estradiol and progesterone hormones for balanced needs in a women's reproductive system as well as to monitor the overall health systems. This proposed structure is suitable for bio-sensing applications due to their cost-effective fabrication and high performance.
原文链接:- NSTL
- Elsevier
