Growth of oxidation-resistive silicene-like thin flakes and Si nanostructures on graphene

We report the growth of Si nanostructures, either as thin films or nanoparticles, on graphene substrates. The Si nanostructures are shown to be single crystalline, air stable and oxidation resistive, as indicated by the observation of a single crystalline Si Raman mode at around 520 cm^-1, a STM image of an ordered surface structure under ambient condition, and a Schottky junction with graphite. Ultra-thin silicon regions exhibit silicene-like behavior, including a Raman mode at around 550 cm^-1, a triangular lattice structure in STM that has distinctly different lattice spacing from that of either graphene or thicker Si, and metallic conductivity of up to 500 times higher than that of graphite. This work suggests a bottom-up approach to forming a Si nanostructure array on a large-scale patterned graphene substrate that can be used to fabricate nanoscale Si electronic devices.     

Carrier transport mechanisms in semiconductor nanostructures and devices

Semiconductor nanostructures have gained importance due to their potential application in future nanoelectronic devices. For such applications, it is extremely important to understand the electrical properties of semiconductor nanostructures. This review presents an overview of techniques to measure the electrical properties of individual and clusters of semiconductor nanostructures using microcopy based techniques or by fabricating metallic electrical contacts using lithography. Then it is shown that current–voltage (I–V) characteristics can be used to determine the conduction mechanism in these nanostructures. It has been explained that various material parameters can be extracted from I–V characteristics. The frequently observed conduction mechanism in these nanostructures such as thermally activated conduction, space charge limited current (SCLC), hopping conduction, Poole Frenkel conduction, Schottky emission and Fowler Nordheim (FN) tunneling are explained in detail.     

Synthesis and optical properties of two novel ZnO flowerlike and spindlelike nanostructures

A new aqueous chemical growth method for generation of ZnO flowerlike and spindlelike nanostructures, transformed from layered basic zinc acetate (LBZA) nanobelts, is developed. The novel as-synthesized ZnO flowerlike and spindlelike nanostructures are mainly due to the pH. They are characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The X-ray diffraction peaks indicate that these ZnO nanostructures prefer to grow along the C-axis. Photoluminescence (PL) measurements show that the ZnO flowerlike nanostructures have strong ultraviolet (UV) emission properties at 380 nm, while no defect-related visible emission can be detected. The good performance for photoluminescence emission makes the ZnO flowerlike nanostructures to be promising candidates for photonic and electronic device applications.     

四角状氧化锌纳米结构的发光特性研究

The tetrapod ZnO nanostructures are synthesized on the Si （100） substrates using the chemical va- por deposition （CVD） method at 1000 ℃. Each nanostructure has four arms which are about 3-10 μm in length and 0.2-1.5 μm in diameter. Further analyses on structure demonstrate that the tetrapod ZnO nanostructures have single crystalline wurtzite hexagonal structure preferentially oriented in c-axis. The photoluminescence （PL） mea- surements of the tetrapod ZnO nanostructures revealed a UV peak at 382 nm corresponding to the free exciton emission, and a green peak at 523 nm arising from deep level emission. For comparative analysis, cathodolumines- cence （CL） spectra obtained from different regions of an individual tetrapod are investigated. Moreover, a possible growth mechanism of the tetrapod ZnO nanostructures is also discussed based on the experimental results.     

An anisotropic thermal-stress model for through-silicon via

A two-dimensional thermal-stress model of through-silicon via (TSV) is proposed considering the anisotropic elastic property of the silicon substrate.By using the complex variable approach,the distribution of thermalstress in the substrate can be characterized more accurately.TCAD 3-D simulations are used to verify the model accuracy and well agree with analytical results (＜ ±5％).The proposed thermal-stress model can be integrated into stress-driven design flow for 3-D IC,leading to the more accurate timing analysis considering the thermal-stress effect.     

Properties of ITO：Zr films deposited by co-sputtering

ITO：Zr films were deposited on glass substrate by co-sputtering with an ITO target and a Zirconium target. Substrate temperature and oxygen flow rate have important influences on the properties of ITO：Zr films. ITO：Zr films show better crystalline structure and lower surface roughness. Better optical-electrical properties of the films can be achieved at low substrate temperature. The certain oxygen flow rates worsen the electrical properties but can enhance the optical properties of ITO：Zr films. The variation in optical band gap can be explained on the basis of Burstin-Moss effect.     

Crystallization of μc-Si on plastic substrate by using a pulsed double-frequency YAG laser

Thin film transistors (TFTs) of microcrystalline silicon (μc-Si) can provide higher mobility and stability than that of a-Siand better uniformity than that of poly-Si TFTs,and it would be more suitable to be applied to larger-area AMOLEDs.By using 2ωYAG laser annealing,crystalline μc-Si thin film on plastic substrate has been investigated and the proper laser energy needed for crystallization has been indicated.It has been found that the dehydrogenation process at 300-450℃ for a few of hours could be omitted by decreasing the H content in the crystallization precursor,which is suitable for laser crystallization on plastic substrates.The crystalline volume fraction (Xc) and the grain size of the resulted μc-Si could be adjusted by controlling the laser energy.By this method,the μc-Si on plastic substrate with Xc and grain size is respectively 85% (at the maximum) and 50 nm.     

Energy-Optimal and Delay-Bounded Computation Offloading in Mobile Edge Computing with Heterogeneous Clouds

By Mobile Edge Computing(MEC), computation-intensive tasks are offloaded from mobile devices to cloud servers, and thus the energy consumption of mobile devices can be notably reduced. In this paper, we study task offloading in multi-user MEC systems with heterogeneous clouds, including edge clouds and remote clouds. Tasks are forwarded from mobile devices to edge clouds via wireless channels, and they can be further forwarded to remote clouds via the Internet. Our objective is to minimize the total energy consumption of multiple mobile devices, subject to bounded-delay requirements of tasks. Based on dynamic programming, we propose an algorithm that minimizes the energy consumption, by jointly allocating bandwidth and computational resources to mobile devices. The algorithm is of pseudo-polynomial complexity. To further reduce the complexity, we propose an approximation algorithm with energy discretization, and its total energy consumption is proved to be within a bounded gap from the optimum. Simulation results show that, nearly 82.7% energy of mobile devices can be saved by task offloading compared with mobile device execution.     

Impact of the dielectric duty factor on magnetic resonance in Ag-SiO2-Ag magnetic absorber

Magnetic absorber in optical frequency can be fulfilled through metamaterials designing. Therein, magnetic resonance in metal-dielectric-metal metasurfaces can be manipulated conveniently, and studying the parameters impacts is the primary for applications. In this work, through changing the grating width and the thickness of silica, the magnetic resonance modes have been studied, the conditions of the phase change zone from magnetic resonance(MR) to Fabry-Pérot(FP) are given out in Ag-SiO₂-Ag grating magnetic metasurfaces. The results indicate that the MR mode in metal-dielectric-metal configuration is mainly decided on the dielectric duty factor other than the sole behaviors of the thickness of dielectric and size of nanostructures. The physical mechanism is elucidated through simulated electromagnetic field distributions using finite difference time domain(FDTD) solution, and numerical analysis of effective refraction index of Ag-SiO₂-Ag magnetic metasurfaces. This study may prompt development of metamaterials in basic research in condensed physics and in optical devices applications.     

A novel mathematical model for coverage in wireless sensor network

1 Introduction With the development of the sensor, wireless communication, and computer science, many researches have been focused on the development of a novel wireless network named wireless Ad-hoc sensor networks. This network can be defined as a network that can be self-organized in Ad-hoc fashion. This includes many sensor nodes and its objective is to sense, collect, and process the information collected by the individual sensor nodes via their cooperation [2]. Because of its high pract…     

Two schemes of perfect teleportation one-particle state by a three-particle general W state

In teleportation, it can be seen that the probability of success is determined by Alice＇s measurement and quantum channel, ff the Alice＇s measurement is appropriate, the teleportation can be successfully realized with the maximal probability. In accordance with transformation operator, two schemes are proposed for teleportation of an unknown one-particle state via a general W state, through which the successful probability and the fidelity of both schemes reach 1. Furthermore, two optimal matches of orthogonal complete measurement bases are given for teleporting an unknown one-particle state.     

MAXIMUM LIKELIHOOD SOURCE SEPARATION FOR FINITE IMPULSE RESPONSE MULTIPLE INPUT—MULTIPLE OUTPUT CHANNELS IN THE PRESENCE OF ADDITIVE NOISE

Blind identification-blind equalization for finite Impulse Response(FIR)Multiple Input-Multiple Output(MIMO)channels can be reformulated as the problem of blind sources separation.It has been shown that blind identification via decorrelating sub-channels method could recover the input sources.The Blind Identification via Decorrelating Sub-channels(BIDS)algorithm first constructs a set of decorrelators,which decorrelate the output signals of subchannels,and then estimates the channel matrix using the transfer functions of the decorrelators and finally recovers the input signal using the estimated channel matrix.In this paper,a new qpproximation of the input source for FIR-MIMO channels based on the maximum likelihood source separation method is proposed.The proposed method outperforms BIDS in the presence of additive white Garssian noise.     

UNI-VECTOR-SENSOR DIRECTION FINDING WITH REGULARIZED ESPRIT

The regularized Least-Squares Estimation method of Signal Parameters via Rotational Invariance Techniques （LS-ESPRIT） is herein proposed for Direction-Of-Arrival （DOA） estimation of non-Gaussian sources with only one acoustic vector-sensor. The Second-Order Statistics （SOS） and Higher-Order Statistics （HOS） of data are fused within a regularization framework. The steering vectors can be blindly identified by the regularized ESPRIT, from which the aim of DOA estimation can be achieved. Several variants of the regularized ESPRIT are discussed. A suboptimal scheme for determination of the regularization parameters is also given.     

An advanced SEU tolerant latch based on error detection

This paper proposes a latch that can mitigate SEUs via an error detection circuit.The error detection circuit is hardened by a C-element and a stacked PMOS.In the hold state,a particle strikes the latch or the error detection circuit may cause a fault logic state of the circuit.The error detection circuit can detect the upset node in the latch and the fault output will be corrected.The upset node in the error detection circuit can be corrected by the Celement.The power dissipation and propagation delay of the proposed latch are analyzed by HSPICE simulations.The proposed latch consumes about 77.5％ less energy and 33.1％ less propagation delay than the triple modular redundancy (TMR) latch.Simulation results demonstrate that the proposed latch can mitigate SEU effectively.     

Crystallization of μc-Si on plastic substrate by using a pulsed double-frequency YAG laser

Thin film transistors （TFTs） of microcrystalline silicon （μc-Si） can provide higher mobility and stability than that of a-Si and better uniformity than that of poly-Si TFTs, and it would be more suitable to be applied to larger-area AMOLEDs. By using 2coYAG laser ann. ealing, crystalline μc-Si thin film on plastic substrate has been investigated and the proper laser energy needed for crystallization has been indicated. It has been found that the dehydrogenation process at 300-450℃ for a few of hours could be omitted by decreasing the H content in the crystallization precursor, which is suitable for laser crystallization on plastic substrates. The crystalline volume fraction （Xc） and the grain size of the resulted μc-Si could be adjusted by controlling the laser energy. By this method, the μc-Si on plastic substrate with Xc and grain size is respectively 85% （at the maximum） and 50 nm.     

Engineering in-plane silicon nanowire springs for highly stretchable electronics

Crystalline silicon (c-Si) is unambiguously the most important semiconductor that underpins the development of modem microelectronics and optoelectronics,though the rigid and brittle nature of bulk c-Si makes it difficult to implement directly for stretchable applications.Fortunately,the one-dimensional (1 D) geometry,or the line-shape,of Si nanowire (SiNW) can be engineered into elastic springs,which indicates an exciting opportunity to fabricate highly stretchable 1D c-Si channels.The implementation of such line-shape-engineering strategy demands both a tiny diameter of the SiNWs,in order to accommodate the strains under large stretching,and a precise growth location,orientation and path control to facilitate device integration.In this review,we will first introduce the recent progresses of an in-plane self-assembly growth of SiNW springs,via a new in-plane solid-liquidsolid (IPSLS) mechanism,where mono-like but elastic SiNW springs are produced by surface-running metal droplets that absorb amorphous Si thin film as precursor.Then,the critical growth control and engineering parameters,the mechanical properties of the SiNW springs and the prospects of developing c-Si based stretchable electronics,will be addressed.This efficient line-shape-engineering strategy of SiNW springs,accomplished via a low temperature batch-manufacturing,holds a strong promise to extend the legend of modem Si technology into the emerging stretchable electronic applications,where the high carrier mobility,excellent stability and established doping and passivation controls of c-Si can be well inherited.     

A IO-MHz SOl-Based Face Shear Square Micromechanical Resonator

A 10-MHz face shear(FS) square micromechanical resonator based on silicon-on-insulator(SOI)technology is presented in this paper. In order to examine the improvement of quality factor as well as motional resistance Rx in this structure, the center-stem anchor is employed in this study. The benefit of anchoring the square in the center, which is the nodal point, is that the energy losses through the anchor can be minimized. Hence, a quality factor value of 2.0 million and the motional resistance of 8.2 k can be obtained with an FS mode resonator via finite element(FE) simulation. The results show the significance of the FS mode in this design, not only in its structure but also in its square-extensional mode and Lame-mode. Additionally, an SOI-based fabrication process is proposed to support the design.     

Small Components of the Wave Function of Electron

In this paper, via an analogy between the wave functions of free electron and free electromagnetic fields, we study the relation between the large components and the small components of the wave function of electron, and show that in some cases the small components cannot be ignored. As an application, we will demonstrate that not only the spin quantum states of a moving electron but also those of a motionless electron can be affected by some special electrostatic fields. This may provide a ne…     

Synthesis and photoluminescence properties of wash-board belt-like ZnSe nanostructures

Washboard belt-like zinc selenide （ZnSe） nanostructures are successfully prepared by a simple chemical vapor deposi- tion （CVD） technology without catalyst. The phase compositions, morphologies and optical properties of the nanos- tructures are investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, high-resolution transmis- sion electron microscopy （HRTEM） and photoluminescence （PL） spectroscop, respectively. A vapor-liquid mecha- nism is proposed for the formation of ZnSe belt-like structures. Strong PL from the ZnSe nanostructure can be tuned from 462 nm to 440 nm with temperature varying from 1000 ℃ to 1200 ℃, and it is demonstrated that the washboard belt-like ZnSe nanostructures have potential applications in optical and sensory nanotechnology. This method is ex- pected to be applied to the synthesis of other II-VI groups or other group＇s semiconducting materials.     

Design and analysis of spectral beam combining system for fiber lasers based on a concave grating

A novel fiber laser spectral beam combining scheme based on a concave grating is presented.The principle of the presented system is analyzed,and a concave grating with blazed structure for spectral beam combining is designed.The combining potential of the system is analyzed,and the results show that 39 Yb-doped fiber laser can be spectrally beam combined via the designed system.By using scalar diffraction theory,the combining effect of the system is analyzed.The results show that the diffraction efficiency of the designed concave grating is higher than 72% over the whole gain bandwidth,and the combining efficiency is 73.4%.With output power of 1 kW for individual fiber laser,combined power of 28.6 kW can be achieved.