Study of microstructural, optical and electrical properties of Mg dopped SnO thin films

Mg doped SnO thin films were fabricated via electron beam evaporator on the glass substrate. The XRD analysis showed that reference and Mg doped SnO thin films were consisted of tetragonal α-SnO phase with preferred directions along (101) and (002) orientations. It was observed that the intensity of the diffraction pattern peaks increased and crystallite size decreased with the Mg doping. Scanning electron microscopy showed that the needle-like particles having length in the range of 0.4–0.6 μm with a diameter of 0.1–0.2 μm are sintered together to form a compact structure of Sn_1?xMg_xO layer. In the Raman spectrum, two active mode (A _2u and E _u ) were observed for Sn_1?xMg_xO thin films. The complex plot (Nyquist plot) showed the data point laying on a single semicircle and the dc resistance increases with the increase of Mg doping concentration.     

PZT含量对PZT-PZN-PNN压电陶瓷材料电性能的影响

采用传统固相法制备了xPb（Zr0.52Ti0.48）O3-（1-x）{Pb（Zn1/3Nb2/3）O3-Pb（Ni1/3Nb2/3）O3}（简称PZT-PZN-PNN）四元系压电陶瓷，研究了不同PZT含量对PZT-PZN-PNN陶瓷的相结构、显微结构、压电性能和介电性能的影响。结果表明：材料的压电常数（d33）、机电耦合系数（％）和介电常数（曲随着PZT含量的增加先增大，后减小，当PZT含量为0.83时，其值达到最大值；随着PZT含量的增加，材料的机械品质因数（Qm）逐渐增大，谐振电阻僻（Rf）和介电损耗（tanδ）逐渐减小。当PZT含量为0.83时，四元系PZT-PZN-PNN压电陶瓷在较低的烧结温度（1000℃）下烧结，其主要的电性能参数如下：d33=477pC/N，Kp=0.71，Qm=98，εf=2228，tanδ=0.0070，Tc=325℃，根据双晶片对压电陶瓷材料的性能要求，该纽份可作为纺织机械中选针器用压电双晶片的侯选材料。     

Some structural,electrical and optical properties of copper phosphate glasses containing the rare-earth europium

Various properties of copper phosphate glass containing small amounts of the rare-earth europium have been investigated in the two glass systems Eu₂O₃-CuO-P₂O₅ and Eu₂O₃-CaO-CuO-P₂O₅. Density and molar volumes showed an increase as Eu₂O₃ replaced CuO and CaO in the glass compositions. Enhanced reduction from Cu²⁺ to Cu⁺ valency states of the ions in the glasses due to the presence of europium has been inferred from the results of electron spectroscopy for chemical analysis, and confirmed by results of electron spin resonance measurements. Corresponding electrical and optical band-gap characteristics, however, showed little systematic variation. The tetrahedral structure of P₂O₅ appeared to dominate the structural characteristics and infrared behaviour of the glass. The results are interpreted in terms of molecular structure, electronic configuration and small polaron hopping models. The role of europium in the glass is discussed.     

Mg2Si电子结构及光学性质的研究

采用基于第一性原理的赝势平面波方法系统地计算了Mg2Si基态的电子结构、态密度和光学性质。计算结果表明Mg2Si属于间接带隙半导体，禁带宽度为0．2994eV；其价带主要由Si的3p以及Mg的3s、3p态电子构成，导带主要由Mg的3s、3p以及Si的3p态电子构成；静态介电常数ε1（0）=18．89；折射率n0=4．3460；吸收系数最大峰值为356474．5cm^-1；并利用计算的能带结构和态密度分析了Mg2Si的介电函数、折射率、反射率、吸收系数、光电导率和能量损失函数的计算结果，为Mg2Si的设计与应用提供了理论依据。     

Superresolution readout system with electrical equalization for optical disks

An electrical equalizer for a superresolution readout system with an optical apodizer is proposed and verified experimentally. This superresolution readout system uses a five-tap transversal filter as the electrical equalizer instead of additional optics to suppress enlarged sidelobes, and it achieves higher resolution than the diffraction-limited system. The transfer function of the electrical equalizer is also derived theoretically. This approach allows fabrication of a readout system with a good signal-to-noise ratio and a compact head.     

Annealing effect on structural, optical and electrical properties of pure and Mg doped tin oxide thin films

This study describes the effect of annealing at different temperatures (400–600 °C) on structural, optical and electrical behaviors of pure and Mg doped tin oxide thin films grown on the glass substrate by electron beam evaporation technique. The transformation of tetragonal to orthorhombic form due to annealing, introduced a change in the optical and electrical properties of pure and Mg doped tin oxide thin films. X-ray diffraction studies or analysis revealed the phase transformation and change in the crystalline size with increase in the annealing temperature. The morphology and roughness of the thin films were studied by Atomic force microscopy. Optical band gap increased with annealing temperature confirms the improvements of crystallinity. The quality of thin films transparency was investigated by UV/Vis-spectroscopy. Photoluminescence of pure and Mg doped tin oxide thin films shows two extra peaks one at 486 nm and other at 538 nm is due to the crystal defect created as a result of annealing temperature. These peaks became stronger and shifted to longer wavelength with increasing the annealing temperature. The complex plot (Nyquist plot) showed the data point laying on two semicircles and the resistance of grains and grain boundaries increases with the increase in annealing temperature for both pure and Mg doped tin oxide thin films.     

Preparation of nanocrystalline Mg doped CdSe thin films and their optical,photoluminescence, electrical and structural characterization

Phosphors used are mostly rare earth doped complex structures. A simple and unique material system of CdSe:Mg nanocrystalline thin films, which efficiently absorb UV (235 nm) and emit broad spectrum of green-yellow region has been prepared by chemical bath deposition method with average particle size of 52.3 nm, measured using AFM images. The optical absorption studies found that CdSe thin film has direct optical band gap, \({E_g}\) of 2.62 eV that shows a blue shift of 0.88 eV compared to the bulk \({E_g}\) value. Optical, electrical, structural and morphological properties were studied by UV–Vis–NIR spectrophotometer, photoluminescence (PL) emission spectra, dc two-probe method, X-ray diffraction (XRD), and atomic force microscope (AFM). Measured electrical resistivity decreased with increase of doping concentration. Activation energy was also calculated. The results confirm that the CdSe:Mg thin films are in the pure cubic phase. The magnesium concentrations also affect the nanocrystalline nature of the CdSe thin films. The optical band gap and surface roughness of CdSe thin films mostly decrease with 5% doping of Mg. The effect of Mg doping on refractive index, extinction coefficient and other optical parameters was also investigated.     

Study of electrical and optical properties of Mn doped ZnS clusters

A simple, easy approach to the synthesis of manganese Mn doped zinc sulphide (ZnS) clusters is reported. The synthesis of Mn–ZnS clusters involved mixing and drying of zinc acetate, sodium sulphide and acrylic acid in appropriate ratio and adding Mn at proper conditions. These clusters were trapped in polyacrylic acid (PAA) to form PAA capping to provide stability. The clusters were characterized using high resolution SEM for morphological investigation; XRD for its crystalline nature; photoluminescence (PL) for optical characterization and electrical conductivity measurement. Clusters of Mn–ZnS were formed of the size ~ 10 nm.     

A study of the electrical and optical properties of the GeO2-TeO2 glass system

Results of measurements of the d.c. electrical conductivity, optical absorption edge and infrared optical absorption of GeO₂-TeO₂ glasses are reported. Conduction in these glasses is found to be electronic and the hopping of polarons seems to be the dominant process in the transport mechanism. The electrical activation energy decreases with the increase of tellurium content and this decrease corresponds to a decrease in the optical energy gap. The optical gap is of the order of 2.74 eV, somewhat lower than for many other oxide based glasses. Most of the sharp absorption bands characteristic of the basic materials GeO₂ and TeO₂ are modified with the formation of broad and strong absorption bands in the process of going from the crystalline to the amorphous state. Density measurements show the glasses to have a compact structure.     

Structure,magnetic, and electrical studies on vanadium phosphate glasses containing different oxides

Glass system with molar composition (60% P₂O₅–30%V₂O₅–10%X) where X is Li₂O, Na₂O, K₂O, and BaO was prepared. The density and molar volume indicate that the density decreases while the molar volume increases with increasing ionic radius of doped oxides. IR studies reveal the coexistence of V⁴⁺ and V⁵⁺ ions (act as glass modifier and glass former, respectively). The observed paramagnetic behavior of samples indicates that V⁴⁺ > V⁵⁺ (the ratio V⁴⁺/V⁴⁺ + V⁵⁺ > 0.52 as obtained from chemical titration analysis). Mott’s model of conduction was applied to discuss DC electrical conduction mechanism. The prepared glass exhibits semiconducting behavior. However, Ba ion is the only ion which did not contribute to the ionic conduction. The conductivity increases with decreasing ionic radius of doped oxides due to high mobility due to their small size. The effect of hopping distance on the electrical conduction and magnetic properties were discussed. An attempt was done to determine the expected temperature of Ba ionic conduction and its ionic activation energy.     

Preparation,and structural,optical and electrical properties of the CdTe1−xSx system

Thin films of the CdTe_1–xS_x system (00.4S_0.6 system showed a maximum optical absorption. It is observed that the optical gap, E_opt, is indirect for (0opt with x in the CdTe_1–xS_x system is not linear and the minimum value of E_opt, was for x=0.3. The addition of copper dopants up to 3% to the CdTe_0.4S_0.6 system reduced the value of E_opt. The electrical conductivity showed two values of activation energy indicating different dominant conduction mechanisms in different temperature ranges.     

Analysis of intrachip electrical and optical fanout

We examine the benefits of electrical isolation in intrachip optical signaling. We calculate the delay and energy metrics of an optical interconnect with fanout driving an electrical load. By examining fanout and including load drivers into delay equations, we make a shift from the general trend of looking at optical interconnects as a replacement for long parasitic wires. Our calculations show that optical fanout provides a large improvement in an Etau2 (energy delay squared) metric and improves performance even at very short intrachip distances. The break-even length corresponds to the wiring length of 250 minimum-size inverters that are compactly laid out. These results provide a compelling reason to further examine the implementation of optical interconnects.     

Study of structural,optical and electrical parameters of ZnSe powder and thin films

Nanocrystalline ZnSe powder and thin film forms have been synthesized via chemical bath deposition technique. The ZnSe thin films are deposited onto ultrasonically clean glass substrates in an aqueous alkaline medium using sodium selenosulphate as Se^2? ion source. The ZnSe powder and thin film are characterized by structural, optical and electrical properties. It is confirmed from X-ray diffraction study that cubic phase is present in ZnSe thin film form with (111) as preferred orientation and hexagonal phase is present in ZnSe powder form with (100) as preferred orientation. Optical absorption measurement indicates the existence of direct allowed optical transition with a wide energy gap and blue shift in the fundamental edge has been observed in both cases. The optical band gap of ZnSe powder is greater than the thin film. The electrical conductivity (both dark and photoconductivity) measurements are also carried out in different temperature range and variation in activation energy has been calculated.     

The influence of different electrolytes on the electrical and optical properties of polymer films electrochemically synthesized from 3-alkylthiophenes

In this study, we observed significant differences in the electrical and optical properties of polymer films electrochemically synthesized from two 3-alkylthiophene monomers on platinum wires in 0.100 mol L^?1 LiClO₄/acetonitrile (ACN) or Et₄NBF₄/ACN, when compared to the following homopolymer films: poly(3-methylthiophene) (P3MT), poly(3-hexylthiophene) (P3HT) and poly(3-octylthiophene) (P3OT), prepared under the same conditions. Electrical impedance spectroscopy was used to assess the resistive and capacitive properties of the polymer films [P3MT and P3HT—CP3(MT-HT); P3MT and P3OT—CP3(MT-OT); P3HT and P3OT—CP3(HT-OT)] at overpotentials determined beforehand by Cyclic Voltammetry. The films synthesized in LiClO₄/ACN with the lowest charge transfer resistance values were CP3(MT-HT) and CP3(MT-OT), and synthesized in Et₄NBF₄/ACN, CP3(HT-OT). In terms of their optical properties, the films synthesized in LiClO₄/ACN exhibited hypsochromic shift of E _g values and a drop in electron affinity values by comparison with homopolymer films and those synthesized in Et₄NBF₄/ACN. Based on Photoluminescence (PL) Spectroscopy it was possible to identify the contributions of the quinone and aromatic segments characteristic of homopolymers in the films synthesized in Et₄NBF₄/ACN. For the films synthesized in LiClO₄/ACN, it was not possible to perform the same comparison because there was a discrepancy between the bands observed in the PL images of these materials and those of the homopolymers, suggesting the formation of not only blend structures but also copolymer films. Using Raman Spectroscopy it was possible to identify aromatic, radical cation and dication segments and verify the higher stabilization of radical cation and dication segments in resistive films. It was also possible to observe changes in the morphological structures of the films by comparison with the homopolymers, in addition to alterations due to changes in electrolyte during synthesis using scanning electron microscopy.     

Study of non-isothermal kinetics, electrical and optical properties of (GaSeTe) films

Ternary Ga_xSe_86−xTe₁₄ amorphous films (x=15 and 36) were prepared by thermal evaporation. The results of differential scanning calorimetry (DSC) at different heating rates are reported and discussed. The glass transition activation energy, E_t, and the crystallization activation energy, E_c, were evaluated by measuring the heating rate dependence of the glass transition, crystallization onset and peak crystallization temperatures. The average calculated values of E_t and E_c are 140.29 and 97.89 kJ/mol, respectively. The electrical conductivity of amorphous Ga_xSe_86−xTe₁₄ thin films with different thickness has been measured in the temperature range (263.2-333.3 K) and this allows the effect of introducing a metallic impurity to be observed. It was observed that conductivity increases with increasing activation energy and with a lowering of the pre-exponential factor, which suggests the results can be explained in terms of hopping conduction. The optical constants of these films were determined by transmission and reflection measurements at normal incidence in the spectral range of 500-800 nm. The refractive index has anomalous behavior in the spectral range 400-500 nm. The refractive index dispersion can be fitted to a single oscillator model.     

室温沉积Cu/ZnO薄膜的光电性能的研究

以ZnO陶瓷靶和金属Cu靶为基础在室温条件下利用直流磁控溅射和射频磁控溅射技术在玻璃衬底上制备了ZnO/Cu多层透明导电薄膜。通过改变溅射金属Cu层的时间等工艺参数,并采用紫外-可见-近红外(UV-Vis-NIR)分光光度计和霍尔测试仪对ZnO/Cu多层结构薄膜的光电性质等进行了分析和研究。ZnO/Cu多层透明导电薄膜的导电性随金属层溅射时间增加有很大的提高,从薄膜的透射谱中发现,Cu层的引入降低了多层结构的可见光透光率。随着多层结构薄膜载流子浓度的增加薄膜的光学带隙Eg下降。