Advanced Materials Research Vol. 811

Abstract: This paper analyses the current state of welding duplex stainless steel (DSS). Despite of well-known procedures of welding DSS by standard methods, nowadays modern technologies brings several issues. Electron beam welding showed the problems with achieving the similar phase composition to base metal. By changing the focusing distance and using the post-heating it was possible to bring extra heat input to weld joint what promoted the creation of austenite. Post-heating was performed by additional electron beam pass. By modification of welding procedure it was possible to obtain the phase composition very similar to base metal.

Abstract: In order to increase data storage density of hard drive, DLC overcoat thickness was decreased to allow read/write head to come closer to magnetic alloy of the disk, andwith maintaining the main purpose of the overcoat to provide good corrosion and mechanical protection for the underlying magnetic recording film under unfavorably environmental conditions and occasional reactions. Base on that the edges of topography will be weak point for deposition films cause of shadow effect during the process, its hard that deposition atomic will stay at the concave and convex of topography. DLC coverage performance at the edge of 3D topography becomes high sensitive with limited DLC films thickness. Currently the 3D profile of magnetic material that needs to protect with DLC, is about 2 nanometers with subnanometres DLC thickness. The enormous of data shrew corrosion pattern was usually happened at the edge of topography. Thus, the accelerated test or indirect methodology was applied for DLC integrity. This investigation was explore the methodology to verify the weakness of DLC films especially at the topography edges which is difficult for any direct metrology tools can pursue. With pore resistance, which related to the film structure, the electrochemical impedance indicated that DLC/Si3N4 is a suitable choice to against corrosion. However topography surface influence to DLC coverage. Controllable surface for DLC deposition also needed well defined. Two types of step height was created as 1 nm and 2 nm on (100) silicon substrate. The 20Å DLC film thickness was deposited on the silicon substrate with promised technique, Filtered Cathodic Vacuum Arch (FCVA). After this process the aluminum (Al) was deposited on the surface of DLC film by using evaporation technique. The silicon substrate was driven to Al surface thro pin holes on the DLC film at 577OC. To detect the pin holes on the DLC film, the aluminum layer was removed by using wet etch chemical process. The SEM image indicates that the square pitting at the edge of DLC film obtained for 2nm step height was around 2nm depth. The latest experiment in this investigation to characterize 2.3 T magnetic moment material degradation with DLC/Si3N4 coating, was performed with electrochemical impedance spectroscopy and AFM. The material with DLC overcoat after exposed to H2SO4 for 30 min, polarization resistance was increased for 2 times from uncoated material. Alternative charge transfer capacitance was reduced as desirable charge current.

Abstract: High performance and device uniformity n-channel low-temperature poly-silicon (LTPS) bottom-gate (BG) thin film transistors (TFTs) with artificially-controlled lateral grain growth have been performed by excimer laser crystallization (ELC). The BG TFTs (W/L = 1.5 μm/1.5 μm) demonstrate field-effect-mobility of 323 cm²/Vs and high I_on/I_off of 9.5 × 10⁸. The proposed BG TFTs reveal the superior electrical characteristics, device uniformity, and reliability than conventional top-gate ones.

Abstract: The rare-earth Eu³⁺ doped BaY₂O₄ red phosphor synthesized by citric acid sol-gel method. The structure, morphology and composition of the red phosphor were characterized by X-ray diffraction, scanning electron microscopy and infrared spectroscopy. The results show that the distribution of the pure phase BaY₂O₄: Eu³⁺ particles after annealing at 800 °C was irregular, small size of particle is 0.2 μm to 0.4 μm. The excitation spectra of synthesized phosphor at 610 nm monitoring were composed of a broadband and a series of sharp peaks, the strongest excitation peak at 466 nm, the secondly at 395nm. It was indicated that BaY₂O₄: Eu³⁺ phosphor matching with the widespread applied the output wavelengths of UV LED and blue LED chips. The main emission spectra of samples under blue light excitation is Eu³⁺ ions ⁵D₀⁷F₂ electric dipole transition with a strong red light, so that the BaY₂O: Eu³⁺ phosphor may be a better candidate for red component for white LED.

Abstract: Associating a perturbation term for the effective refractive index which may depend ontime or position we describe the extremal features for the surface plasmon fields propagating on aroughness metal surface. This representation allows us to interpret the surface optical field as ageodesic flow which in principle enables us to associate coherence features to plasmon modes andto analyze the stability of the surface fields under small perturbations of the refractive index.

Abstract: The purpose of the paper is present the new result of electrical properties of Pt-doped silicon Schottky diodes that are fabricated by using CMOS technology. The results show the comparison of electrical properties namely current-voltage and capacitance characteristics between undoped and Pt-doped Schottky diode. The current characteristics of Pt-doped diode are decreased about 2 to 3 orders in term of reverse bias. As well as in case of forward bias, the current is slightly decreased. Schottky barrier height after Pt doping was increased from 0.84 eV to 0.86 eV. The built-in voltage of Pt-doped diodes was increased from 0.38 V to 0.42 V. The C-V characteristics after Pt doping is decreased about 5 pF. The change of electrical properties are caused by Pt because Pt atoms in silicon can occupy interstitial sites and change the trapping center. This paper will study and analyze the effect of Pt atom in silicon bulk of Schottky diode.

Abstract: The purposeof this research article is present electrical characteristic of Pt-doped silicon photodetector compare with undoped silicon photodetector. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of Pt-doped detector were investigated. In this experiment, the results of Pt-doped detector show that the dark currentisobviously decreased and the photocurrent is decreased about 9 to 10 orders. Furthermore, the capacitance characteristic isslightly increased about 0.15 pF. The effects platinum on silicon indicated the carrier in silicon have been changed.

Abstract: Mesa diodes were irradiation by electron beam at various doses of 25, 50 and 75 kGy to find optimum dose for controlling minority carrier lifetime. The experiment result shows that electron beam can reduce minority carrier lifetime from 24.3 ns to 14.8, 9.5 ns and 7.9 at dose of 25, 50 and 75 kGy, respectively. However, the result of electron beam is not only reduce the lifetime but also effected to other electrical properties such as increasing in saturation current density about 2-3 times, increasing in reverse leakage current density about 3 times. Dominant cause of reverse leakage is increasing in generation current via center traps which formed by the irradiation.

Abstract: This paper mainlyintroduces the basic optical principles of light. Using He-Ne laser and pinhole configure collimated illumination, measuring the index of refraction by minimum deviation method, and measuring the birefringence use of wedge method by transmission optical microscope. In addition, give the results and discussion of the whole experiments.

Abstract: Microstructure is an important factor that influences the mechanical properties of recycled aggregate concrete (RAC). This paper was devoted to an investigation of the relationship between mechanical properties and porosity, hydrate, microstructure of interfacial transition zone (ITZ) in RAC. The result showed that mechanical properties of RAC can be further enhanced with lower porosity, and there was a good linear relation, whereas it did not exist between compressive strength of RAC and average pore diameter. Fine active particles and the hydrate were formed into the cracked and loose layer of ITZ in RAC by A tripe mixing method (TM). Through SEM observation, it is expected that the compressive strength of the RAC can be improved by modifying the porous microstructure and hydrate in ITZ.