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[IEEE 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Kiev (2018.4.24-2018.4.26)] 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Investigation of the Structure and Optical Properties of Thin Copper Films
摘要： Copper nanolayers were formed using the vacuum magnetron-assisted sputtering in various technological modes (sedimentation speed, working pressure, discharge power). Results of microstructural study of the 1 nm to 65 nm thick copper nanofilms deposited on quartz, glass and silicon substrates are presented. Spectra of transmission and reflection coefficients of the copper nanofilms were studied in the wavelength range from 0.2 μm to 1.1 μm. The transmission and reflection spectra of films correspond well to the known spectra of bulk materials. The obtained results are of practical importance for development of nanostructural systems with the preset optical properties and for design of functional devices to be used in optoelectronics, information and energy-saving technologies.
关键词： transmission spectrum,microstructure,nanofilms,reflection spectrum
更新于2025-09-23 15:23:52
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Length-Dependent Electronic Transport Properties of the ZnO Nanorod
摘要： The two-probe device of nanorod-coupled gold electrodes is constructed based on the triangular zinc oxide (ZnO) nanorod. The length-dependent electronic transport properties of the ZnO nanorod was studied by density functional theory (DFT) with the non-equilibrium Green’s function (NEGF). Our results show that the current of devices decreases with increasing length of the ZnO nanorod at the same bias voltage. Metal-like behavior for the short nanorod was observed under small bias voltage due to the interface state between gold and the ZnO nanorod. However, the influence of the interface on the device was negligible under the condition that the length of the ZnO nanorod increases. Moreover, the rectification behavior was observed for the longer ZnO nanorod, which was analyzed from the transmission spectra and molecular-projected self-consistent Hamiltonian (MPSH) states. Our results indicate that the ZnO nanorod would have potential applications in electronic-integrated devices.
关键词： current–voltage (I–V) curves,molecular-projected self-consistent Hamiltonian (MPSH),transport properties,zinc oxide (ZnO) nanorod,transmission spectrum
更新于2025-09-23 15:23:52
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Study on Band-Gap Behaviors of 2D Hierarchical Re-Entrant Lattice Structures
摘要： An investigation of Poisson’s ratios and band gap behaviors of 2D hierarchical re-entrant lattice structures is conducted using finite element method (FEM). The structure with a hierarchy order n (n≥1) is constructed by replacing each outmost vertex of the re-entrant octagons of a hierarchical structure of hierarchy order n?1 with a smaller self-similar re-entrant octagon. The dispersion relation and transmission spectrum of the proposed hierarchical structures are analyzed based on the Bloch’s theorem. The effects of geometrical parameters, order of rotational symmetry and orientation angle of some types of re-entrant polygon cores on the lattice Poisson’s ratio and band gap structures are also investigated. Results show that the re-entrant structures with first order hierarchy exhibit a wider band gap and a stronger attenuation effect compared with structures without structural hierarchy. The first order 2D hierarchical re-entrant structure with a negative Poisson’s ratio of ?0.032 exhibits the widest band gap, 17.8% wider than that of the zeroth order 2D re-entrant structure. The order of rotational symmetry and the orientation angle of the re-entrant polygon cores of the lattice have a strong impact on the lattice Poisson’s ratio and band structures.
关键词： re-entrant,negative Poisson’s ratio,band gap,hierarchical structure,transmission spectrum
更新于2025-09-23 15:23:52
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Spectra (UV-Visible, IR transmission) of Sc3+, Fe3+ and Cu2+ tri-doped LiNbO <sub/>3</sub> crystals with various [Li]/[Nb] ratios
摘要： The Sc:Fe:Cu:LiNbO3 crystals were grown with Fe3+(0.3 wt.%), Cu2+(0.1 wt.%) and Sc3+(1 mol.%) by the Czochralski method with various [Li]/[Nb] ratios (0.946, 1.05, 1.20 and 1.38). The influence of the [Li]/[Nb] ratios on the defect structure of Sc:Fe:Cu:LiNbO3 crystals was analyzed by the UV-Visible spectra and IR transmission spectra. The spectra show that the absorption edge shift to the red with [Li]/[Nb] ratios enhancing. The Sc:Fe:Cu:LiNbO3 crystals with [Li]/[Nb] ratio of 1.05 is nearly stoichiometric. A new narrow OH- associated vibrational peak at 3505 cm-1 was revealed in Sc:Fe:Cu:LiNbO3 crystals with the ratio of [Li]/[Nb] = 1.38. It is attributed to the (Sc2-Nb)-(OH)-. The results show that the defect structure changes with the [Li]/[Nb] ratios variation.
关键词： IR transmission spectrum,Sc:Fe:Cu:LiNbO3 crystal,UV-Visible spectrum
更新于2025-09-23 15:22:29
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THz photodetector using sideband-modulated transport through surface states of a 3D topological insulator
摘要： The transport properties of the surface charge carriers of a three dimensional topological insulator under a terahertz (THz) field along with a resonant double barrier structure is theoretically analyzed within the framework of Floquet theory to explore the possibility of using such a device for photodetection purposes. We show that due to the contribution of elastic and inelastic scattering processes in the resulting transmission, side-bands are formed in the conductance spectrum. This side band formation is similar to the side-bands formation in cavity transmission spectra in an optical cavity and this information can be used to detect the frequency of unknown THz radiation. The dependence of the conductance on the bias voltage, the effect of THz radiation on resonances and the influence of zero energy points on the transmission spectrum are also discussed.
关键词： THz radiation,Floquet theory,surface states of topological insulators,side bands in transmission spectrum
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Spectral Features of a Multi-Periodical Metamaterials
摘要： We numerically investigate the spectral properties of multi-periodic metamaterials of various configurations (the planar double-periodic photonic crystal and the bulk double-periodic magnetophotonic crystal) in the frequency range 15-45 GHz. In the first part of this paper we describe investigation of structure of the planar double periodic photonic crystal (PDPPC) which consists of two planar photonic crystals with large and small periods. A PDPPC unit cell consists of a series-connected narrow and wide segments of a microstrip transmission line. In the second part of this paper we will discuss results of investigation of a double-periodic magnetophotonic crystal (DPMPC) which consists of 3 unit cells. Each cell consists of periodically located 9 dielectric layers of quartz and teflon. On the border of the cell there is one layer of ferrite. We showed that both for a PDPPC and for a DPMPC in the transmission spectrum of these structures under study, a number of features arise: namely, narrow transmission peaks caused by the superposition of two spectra (with large and small periods) are observed in the stop bands of the spectrum. Such features may further allow the creation of a narrow-band filter for several frequencies for both planar structures and bulk ones.
关键词： magnetophotonic crystal,multi-periodical metamaterial,stop band,pass band,planar photonic crystal,transmission spectrum
更新于2025-09-19 17:13:59
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Electromagnetically induced transparency and bound in continuum states in double Aharonov-Bohm coupled rings
摘要： We investigated electromagnetic induced transparency (EIT) resonances and bound in continuum (BIC) states in a simple mesoscopic structure made of double Aharonov-Bohm rings of lengths d1 and d2 threaded by a magnetic flux and coupled by a wire of length d0. These investigations are accomplished through an analysis of the amplitude of the transmission coefficient obtained using the Green’s function method. This structure may exhibit a large band gap and an EIT resonance in the transmission spectrum without introducing any impurity in one arm of the loop. In addition, we show that the shape of the EIT resonances and the width of the band gaps can be tuned by means of the magnetic flux and the geometry of the structure. These results may have important applications for electronic transport in mesoscopic systems.
关键词： Transmission spectrum,EIT resonance,Bound in continuum states,Aharonove-Bohm flux,Green’s function
更新于2025-09-12 10:27:22
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Finite-Difference Time-Domain Analysis of Tapered Photonic Crystal Fiber
摘要： This paper brief about the simulation of tapered photonic crystal fiber (PCF) LMA-8 single-mode type based on correlation of scattering pattern at wavelength of 1.55 μm, analyzation of transmission spectrum at wavelength over the range of 1.0 until 2.5 μm and correlation of transmission spectrum with the refractive index change in photonic crystal holes with respect to taper size of 0.1 until 1.0 using Optiwave simulation software. The main objective is to simulate using Finite-Difference Time-Domain (FDTD) technique of tapered LMA-8 PCF and for sensing application by improving the capabilities of PCF without collapsing the crystal holes. The types of FDTD techniques used are scattering pattern and transverse transmission and principal component analysis (PCA) used as a mathematical tool to model the data obtained by MathCad software. The simulation results showed that there is no obvious correlation of scattering pattern at a wavelength of 1.55 μm, a correlation obtained between taper sizes with a transverse transmission and there is a parabolic relationship between the refractive index changes inside the crystal structure.
关键词： scattering pattern,photonic crystal fiber,optiwave,transmission spectrum,tapered
更新于2025-09-10 09:29:36
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Enhanced sensitivity of hemoglobin sensor using dual-core photonic crystal fiber
摘要： A Hemoglobin (Hb) biosensor based on dual-core photonic crystal fiber is proposed and analyzed. In this paper, the effective refractive index dependency on the Hb concentration within a blood sample is utilized in obtaining the transmission spectrum variation. The results are calculated using full vectorial finite element method. Through this study, the effect of the structure geometrical parameters on the sensor performance is optimized to maximize the sensor sensitivity. The numerical results show a sensitivity of 8.013 nm/g/dL for the X-polarized mode at 3.7 cm fiber length and 7.68 nm/g/dL for the Y-polarized mode at 3.2 cm fiber length of the proposed sensor.
关键词： Coupling length,Finite element method,Transmission spectrum,Dual-core photonic crystal fiber,Hemoglobin concentration
更新于2025-09-10 09:29:36