Advanced Materials Research Vols. 538-541

Abstract: High quality La0.9Sr0.1CoO3 (LSCO) thin films grown on 5° vicinal cut LaAlO3 (LAO) (100) substrates were deposited by pulse laser deposition (PLD). Laser induced thermoelectric voltage (LITV) was detected instantly with fast response time and extremely narrow full width at half maximum (FWHM) when 248 nm pulse laser radiated on the surface of LSCO thin films. These merits of LSCO thin films make it one ideal material to fabricate light detectors and photosensitive device. With the increase of pulse laser energy, the peak voltages increase linearly, so LSCO thin films can be used to make high precision laser energy/power meter.

Abstract: The DC plasma chemical vapor deposition (DC-PCVD) method was a promising technique to fabricate CVD diamond coatings in industry, because it has many good properties, such as high grown rate of diamond films, big grown area, high qualities, and cost effective. In the present work, we synthesized diamond films on cemented carbide (YG6) substrates, and studied the different nitric acid aqueous solution treatment durations influence on diamond nucleation stage. The results indicated that well-chosen nitric acid aqueous solution treatment durations should be selected. For too short treatment times, the residual Co will promote the carbon transform from diamond metastable phase into graphite stable phase. On the other side, too long treatment times will consume too much Co, which will lead to the shortage of cohesive body, and finally the crackers in the bulk propagated and peeled off with the diamond films well grown on WC grains.

Abstract: The thin film of (103)-oriented aluminum nitride (AlN) is an attractive piezoelectric material for the applications in film bulk acoustic wave resonator (FBAR) devices. Due to the bulk acoustic wave (BAW) properties of (103) oriented AlN films, it can excite a quasi-shear mode (velocity = 5,957 m/s, K² = 3.8%) that can be used for FBAR liquid sensor and even loss less than the FBAR device with (002) oriented AlN films. In this research, the (103) oriented AlN films were successfully deposited onto (100) silicon substrate by radio frequency (RF) magnetron sputtering. Different sputtering pressures (1m torr, 3m torr, 5m torr, and 7m torr) were discussed in this experiment process. Comparisons were made on their crystalline structures with X-ray diffraction (XRD) and the surface morphologies was investigated by the atomic force microscopy (AFM). The result exhibited the optimal sputtering pressure is 5m torr. The optimal (103) oriented AlN films have the strongest XRD intensity, the smallest full width at half maximum (FWHM) value (0.6°), the largest grain size (15.78nm) and the smooth surface roughness (Ra=3.259nm).

Abstract: Water-tight junction box (WJB) is one of key underwater vehicle technologies, which is indispensible in nowadays underwater engineering. Taking the advantage of large deformation range and corrosion resistance characters of the titanium material, this paper utilizes the titanium thin film material to put forward a titanium film pressure adaptive compensator (TFPAC) which solves the pressure problem and improves the reliability of the WJB greatly. The finite element analysis (FEA) software ANSYS is used to analyze the stress and strain condition of the titanium film when the film is suffering the internal pressure in the working condition. The feasibility and reliability of the Pressure Self-adaptive Water-tight Junction Box (PSAWJB) is tested and verified by hyperbaric chamber tests.

Abstract: This research presents the development of parylene thin-film deposition from the micrometer scale to nanometer scale. Processes improved film uniformity by 6% in the nanometer scale to meet the requirements of new applications of parylene, such as the delamination layer of organic light-emitting diodes, the dielectric film of through-silicon-via, and water-proofing mobile phones. The application and process of water-proofing mobile phones is also examined. The tested mobile phone was coated with a 0.5 μm parylene coating and functioned properly while submerged underwater. The mobile phone is still operational; thus, nanoscale parylene deposition is a novel application for water-proofing mobile phones. The application does not concern problems associated with parts assembly or damaged rubber material.

Abstract: Polyethersulfone (PES) flat sheet membranes were prepared via phase inversion induced by immersion precipitation from a novel lower critical solution temperature (LCST) system containing PES, 1-butanol and N, N-dimethylacetamide. And the effect of coagulation bath temperature on the properties and structure of PES membranes were investigated. The results show that the pure water flux increases and the tensile strength decreases as the coagulation temperature increases form 20°C to 50°C. Besides, the SEM images shows that all of the membranes prepared from a LCST system at different CBT own sponge-like structures.

Abstract: The paper is investigated the polarization properties and mechanical behavior of new piezoelectric polymer material plates by experimental procedures and finite element analysis. In this study, the PVDF materials is used to produce the piezoelectric polymer layer and the coating film, we have provided a nice procedures for manufacturing piezoelectric polymer plates (PVDF). In order to find the proper proportion of the PVDF to achieve the best material properties, the mechanical behavior of displacements and stresses for the electrets is investigated by experimental measurement and finite element analysis (with ANSYS). It is investigated whether the thicknesses of specimens are affected the polarization. The paper is presented modal analysis techniques for piezoelectric thin plates.

Abstract: The gallium and nitrogen co-doped tin oxide (SnO2 :Ga-N) films have been prepared on α-Al2O3 (0001) substrates at 500°C by metalorganic chemical vapor deposition (MOCVD) method. The relative amount of Ga (Ga/(Ga+Sn) atomic ratio) was 8%. The flow rate of gaseous NH3 injected into the reactor chamber varied from 25sccm to 55sccm. According to the XRD patterns, the film grown at the flow rate of 25sccm has the best crystalline structure. Subsequently, a series of co-doped SnO2 films with the Ga concentration varying from 1% to 12% and the flux of 25sccm for NH3 were fabricated. Post-deposition annealing of the films was carried out at different temperatures for 2 h in nitrogen atmosphere. The structural, electrical and optical transmittance properties of the films have been investigated. For the as-deposited films, except that the film with 12% Ga doping has the amorphous structure, other films have the rutile structures of pure SnO2 with a strong (2 0 0) preferred orientation. After annealing, the structures of all films have changed obviously. Especially, the 12% Ga doping film has the polycrystalline structure also with the (200) preferred orientation. The average transmittances for all the films in the visible range were over 85%. The values of the band gaps varied from 3.3eV to 3.5eV for the as-deposited films and 3.7-3.9eV for the annealed ones. The electrical properties of the as-deposited films varied with the Ga content and were being discussed in detail.

Abstract: This research for the membrane stiffening manufacture, thickness, weight, manufacturing parameters, stiffness and surface uniformity was discussed. The used of hand rough paper as membrane substrate, and used of roller coating, spray coating of coating methods, and it carried on membrane stiffening process of carbon nanotubes. On the increase smallest weight, it had been a large increase in stiffness, and the flat speakers sound pressure curve smoother. Used different proportion of carbon nanotubes mixture of different resin to membrane stiffening, used SEM to detect the carbon nanotubes stiffening of the membrane surface coating uniformity, even different coating of compare thickness with weight of increase percentage. It used tensile test to explore different coating methods of Young's modulus of the difference. Then, we was manufactured the small plane speaker (L33mm×W21mm×H12mm) according to the various membrane stiffening and measure the sound pressure curve, and it contrasted with computer-aided analysis software obtained the theory of sound pressure curves.