Gold nanocones fabricated by nanotransfer printing and their application for field emission

Arrays of gold nanocones have been fabricated by the nanotransfer printing (nTP) method and we have utilized these nanocones for field emission. By the nature of the printing, any shape of metal structure can be fabricated only at desired locations and a step-and-repeat process, which enables large-area fabrication, is possible. We demonstrate step-and-repeat printing with gold nanocone patterns occupying an area of 9?mm × 8?mm.     

Coplanar amorphous silicon thin film transistor fabricated by inductively-coupled plasma CVD

The electrical and optical properties of the a-Si:H films deposited by inductively-coupled plasma chemical vapour deposition (ICP-CVD) have been investigated. The ICP-CVD a-Si:H films deposited at 30 mTorr exhibited the deposition rate of 0.9 Å/s and the hydrogen content of 17 at.%. A novel coplanar self-aligned a-Si:H thin film transistor has been fabricated using Ni-silicide gate and source/drain contacts. The coplanar a-Si:H TFT exhibited a field effect mobility of 0.6 cm²/Vs, a threshold voltage of 2.3 V, a subthreshold slope of 0.5 V/dec.     

Elastic modulus determination of a thin layer

The titanium alloy TA6V was nitrogen implanted to improve its wear resistance. In order to extract the value of the elastic modulus of the thin layer that is formed by ion implantation of this titanium alloy, a modelling taking into account different features occurring during implantation is considered, namely erosion, concentration profile and nature of the layer. Then, the elastic modulus of the thin layer is deduced. The estimated value is shown to be consistent with the formation of a TiN rich layer about 0.2 μm thick. In this paper, a procedure based on the resonance frequency of a cantilever is presented leading to the optimisation of the measurement. Then the actual modelling proposed above is described and reliability of calculated values is discussed.     

Step-wise Ag thin film patterns fabricated by holographic lithography

A laser-induced thermo-elastic removal was used to pattern nanostructured silver thin films solution-deposited on the glass substrate. We show that sharp-edged patterns can be fabricated under an interference-generated gradual intensity profile. The etching behavior and the resulting pattern morphology were very sensitive to the cohesion of the film and its adhesion to the substrate, being both modified by the post-deposition annealing process. The fabrication of step-wise one-dimensional (1D) and 2D patterns at the micrometer scales is demonstrated by holographic lithography using an Nd:YAG pulsed laser, along with a discussion on the effect of film cohesion and adhesion.     

Characteristics of bottom-gate low temperature nanocrystalline silicon thin film transistor fabricated by hydrogen annealing of gate dielectric layer

Thin film transistors having nanocrystalline silicon as an active layer were fabricated by catalytic-CVD at a low process temperature (≤ 200 °C). The tri-layer of the bottom-gate TFT was deposited continuously inside the Cat-CVD reactor. In order to improve the quality of the gate dielectric layer an in-situ hydrogen annealing step was introduced in between the silicon nitride and the nanocrystalline silicon deposition steps. The in-situ hydrogen annealing was effective in reducing the hysteresis in the C-V characteristics and in enhancing the breakdown voltage by decreasing the defects inside the SiN_x film.     

Thermoelectric properties of boron-carbide thin film and thin film based thermoelectric device fabricated by intense-pulsed ion beam evaporation

Crystallized B₁₃C₂ thin films were fabricated by intense pulsed-ion beam evaporation (IBE) method. Electrical conductivity and Seebeck coefficients of the obtained films were 1×10^—4 l/Ωm and 200 μV/K at 1000 K, respectively. These values were comparable to those of bulks. For the application of the thin films, since reasonable thermoelectric (TE) properties were confirmed for the B₁₃C₂ films fabricated, we attempted to develop ’in-plane’ type TE device using B₁₃C₂ and SrB₆ as p-type and n-type elements, respectively. With applying temperature difference to the fabricated device, thermo-electromotive force and electrical power were generated from the device we made, indicating that the device worked as a TE device. To the best of our knowledge, this is the first demonstration of the TE device composed of only boron-rich solids.     

Crystallization of amorphous silicon thin film by using a thermal plasma jet

Amorphous silicon (a-Si) films deposited on glass substrates were crystallized using a thermal plasma jet and the treated films are analyzed to find the relationship between plasma characteristics and crystallization process conditions. The crystallization process conditions were found to have different optimal operating regimes depending on the nozzle geometry. Numerical analysis of the thermal plasma jets showed that the different operating regimes for crystallization were caused by modifications of the plasma characteristics by the nozzle geometry. It is revealed that a stepped-divergent nozzle is more efficient for the thermal plasma annealing process than the conventional cylindrical one due to the broadened high-temperature region and the lowered axial velocity in the plasma jet.     

The bending of silicon wafers by thin polycrystalline silicon film deposition and by film doping using boron diffusion

The existence of stress at the interface between a monocrystalline silicon substrate and a thin (under 1 μm) polycrystalline silicon film was demonstrated using X-ray topography. The wafer-bending direction was studied for a polycrystalline film doped by boron prediffusion and by prediffusion followed by drive-in diffusion. Wafer bending in the presence of SiO₂ thermal growth between the monocrystalline substrate and the polycrystalline film was also investigated. The causes of the wafer bending and its change during polycrystalline film doping are discussed.     

Elastic constants determination of thin cold-rolled stainless steels by dynamic elastic modulus measurements

Temperature dependence of elastic constants of thin cold-rolled stainless steel has been measured by using the acoustic resonance method. Identification of the vibration mode has been examined numerically and experimentally. The elastic constants at room temperature have also been measured by the pulse echo method. In addition, the texture effect on the elastic constants has been analysed by assuming the specimen has orthorhombic structure.     

Large-area flexible 3D optical negative index metamaterial formed by nanotransfer printing

Negative-index metamaterials (NIMs) are engineered structures with optical properties that cannot be obtained in naturally occurring materials. Recent work has demonstrated that focused ion beam and layer-by-layer electron-beam lithography can be used to pattern the necessary nanoscale features over small areas (hundreds of μm(2)) for metamaterials with three-dimensional layouts and interesting characteristics, including negative-index behaviour in the optical regime. A key challenge is in the fabrication of such three-dimensional NIMs with sizes and at throughputs necessary for many realistic applications (including lenses, resonators and other photonic components). We report a simple printing approach capable of forming large-area, high-quality NIMs with three-dimensional, multilayer formats. Here, a silicon wafer with deep, nanoscale patterns of surface relief serves as a reusable stamp. Blanket deposition of alternating layers of silver and magnesium fluoride onto such a stamp represents a process for 'inking' it with thick, multilayer assemblies. Transfer printing this ink material onto rigid or flexible substrates completes the fabrication in a high-throughput manner. Experimental measurements and simulation results show that macroscale, three-dimensional NIMs (>75?cm(2)) nano-manufactured in this way exhibit a strong, negative index of refraction in the near-infrared spectral range, with excellent figures of merit.     

Oxidation of the surface of a thin amorphous silicon film

The oxidation of clean crystalline silicon surfaces is self-limiting at moderate oxygen pressures (10^− 5 Pa) and temperatures (500 °C), forming 0.7-0.8 nm thick oxide layers. This study looks at the oxidation of a surface of a thin amorphous silicon film to establish if a similar mechanism is active in this case. We have devised a special experimental procedure to check the oxidation mechanism of thin amorphous silicon films. For the spectroscopic investigations we used photoemission with synchrotron radiation with the highest possible surface sensitivity and resolution. This permits a detailed decomposition of the Si 2p spectral details, using a mathematical decomposition procedure. The results clearly show that the oxidation mechanism of the surface of an amorphous silicon film under similar conditions is severely hindered compared to cases of crystalline substrates, indicating less reactivity at the surface and less transport of oxygen into the amorphous material.     

塑料薄膜凹版水性油墨

目前国内塑料凹板油墨以溶剂型油墨为主,几乎占到凹印油墨成份的50%.现在正逐步推广,水做溶剂制成的环保型液状油墨.具有不燃、不爆、无毒、无刺激味、墨性稳定、色彩鲜艳、高光泽、不腐蚀印版、操作简便、印刷成本低、印后附着力好、抗水性强、干燥迅速等特点.用水性油墨印刷的产品完全无毒,生产环境环保,最大特点是减少了有机挥发物VOC向大气中的排放量.水性油墨是目前各种油墨中惟一经过美国食品药品协会认可的无毒油墨.     

Elastic modulus of 316 stainless steel lattice structure fabricated via binder jetting process

This study mainly evaluates the elastic modulus of 316 stainless steel lattice structures fabricated via binder jetting process. In this present research, both solid and lattice samples are designed and fabricated by binder jetting process for two different types of mechanical tests. Besides experimental study, a numerical model based on energy approach has been proposed to predict the effective elastic modulus of fabricated lattice samples. By comparing the calculated results of the proposed numerical model with the experimental results, the established model is proved to be validated. This numerical model can be used to determine the parameters of lattice structures fabricated by binder jetting process for desired mechanical properties. At the end, both advantages and disadvantages of the lattice structures fabricated by binder jetting process are analysed. Based on this analysis, the potential application and future research work are pointed out.     

Organic thin film transistor using silver electrodes by the ink-jet printing technology

We have developed a conductive ink containing silver nanoparticles from which the electrodes for organic thin film transistor were directly patterned by ink-jet printing. Nano-sized silver particles having ∼ 20 nm diameter was used for a direct metal printing. Silver conductive ink was printed on the heavily doped n-type silicon wafer with 200-nm thick thermal SiO₂ layer as a substrate. To achieve a high line resolution and smooth conductive path, the printing conditions such as the inter-drop distance, stage moving velocity and temperature of the pre-heated substrates were optimized. After the heat-treatment at temperatures of 200 °C for 30 min, the printed silver patterns exhibit metal-like appearance and the conductivity. To fabricate a coplanar type TFTs, an active material of semiconducting oligomer, α,ω-dihexylquaterthiophene (DH4T) in a chlorobenzene was deposited between the ink-jet printed silver electrodes by drop casting. The OTFT with the ink-jetted source/drain electrodes shows general performance characteristics with good saturation behavior and no significant contact resistance as compared to the one with vacuum deposited electrodes. The electrical characteristic parameters of OTFT show the mobility of 1.3 × 10^− 3 cm² V^− 1 s^− 1 in the saturation regime, on/off current ratio over 10³, and threshold voltage of about − 13 V.     

磁控溅射法制备WO3薄膜及其非线性电学性质

利用射频磁控溅射方法在石英玻璃基片上制备了WO3薄膜,测量了薄膜的伏安特性和显微结构。实验表明实验制备了颗粒小于100nm的WO3多晶膜,薄膜具有良好的非线性电学行为,其非线性系数在0.1-1mA的范围内可达到10以上。简略讨论了WO3薄膜的非线性电输运机理。     

Luminescence characteristics of ZnS:Cu thin film electroluminescent devices fabricated by sputtering

A ZnS:Cu electroluminescent (EL) device was fabricated by sputtering and its luminescence properties were examined. The structure of the fabricated device was glass/Si_xN_y/ZnS phosphor/Si_xN_y/Al. The luminescence spectrum of the device showed two peaks, one blue and the other yellow. The blue peak is created by excitation and recombination of Cu atoms, and can be used for creating blue EL devices.     

A new thin film scanning head for magnetic printing

Magnetic printers are subject to serious limitations, due either to the requirement to move the printing head, or to use multiple heads. The purpose of this paper is to describe the principle of a new head which allows a microline to be recorded by scanning a stress in a head which has magnetostrictive pole pieces. Stress characteristics are described and the changes in the magnetic behaviour of two suitable stress sensitive magnetic alloys are given. Finally, the head limitations are discussed.     

纳米硅薄膜及其太阳电池研究进展

纳米硅薄膜具有新颖的结构特征和一系列独特的物理性质,可望应用于新型光电子器件、量子功能器件、集成电路等领域.本文综述了纳米硅薄膜的研究现状及其优良的光电性能和纳米硅薄膜太阳电池的研究进展,指出在生产制备与性能方面纳米硅薄膜太阳电池所具有的优势,具有良好的发展前景.