The effect of adjusting the stroke value of jet dispenser on the performance of glucose biosensor with gold-plated electrode.

This study investigates the effect of dispensing glucose oxidase enzyme onto the reaction zone of a golden electrode via a jetting dispenser. Each droplet of enzyme solution dispensed onto the reaction zone of golden electrode weighs exactly the same at around 0.4 mg. This study shows that the spring and needle assembly can be controlled by adjusting the stroke value of the stroke adjustment knob to generate different jet dispensing effects, thus affecting the change of droplets of glucose oxidase enzyme solution within the reaction zone of the golden electrode. This study performs experiments using three stroke values, which are 0.8, 1.2, and 1.6 mm. The experimental results show that adjusting the stroke value to change the droplet of the dispensing liquid will significantly affect the accuracy of the test strip reading value. When the stroke value is adjusted to 1.5 mm, the standard deviation of the test strip is 3.8 mg/dL and the coefficient of variation is 4.1%-6.1%. The study suggested that adjusting the stroke value can stabilize the dispensed droplet to increase the stability of test strip reading, improving the accuracy of the test strip reading. This adjustment method can also be applied to the process of other biochemical sensors.

Effect of filling pressure in jetting dispenser on the performance of blood glucose test strips using immersion gold-plated printed circuit board.

To ensure accurate glucose readings when dispensing glucose oxidase enzyme solution from a jetting dispenser onto glucose test strips fabricated from an immersion gold-plated printed circuit board, every drop of the enzyme solution needs to have nearly the same weight and to be dispensed on the reaction zone of the test strips. Experimental results in this study show that the filling pressure in the fluid reservoir containing the glucose enzyme solution to dispense onto the test strips significantly affect the glucose test results. A filling pressure of 12 psi produces test strips with lower coefficient of variation and standard deviation than 10 and 14 psi. Proper filling pressure for dispensing glucose enzyme onto glucose test strips needs to be determined for any enzyme compound formulation.

Investigation of Rapid Low-Power Microwave-Induction Heating Scheme on the Cross-Linking Process of the Poly(4-vinylphenol) for the Gate Insulator of Pentacene-Based Thin-Film Transistors.

In this study, a proposed Microwave-Induction Heating (MIH) scheme has been systematically studied to acquire suitable MIH parameters including chamber pressure, microwave power and heating time. The proposed MIH means that the thin indium tin oxide (ITO) metal below the Poly(4-vinylphenol) (PVP) film is heated rapidly by microwave irradiation and the heated ITO metal gate can heat the PVP gate insulator, resulting in PVP cross-linking. It is found that the attenuation of the microwave energy decreases with the decreasing chamber pressure. The optimal conditions are a power of 50 W, a heating time of 5 min, and a chamber pressure of 20 mTorr. When suitable MIH parameters were used, the effect of PVP cross-linking and the device performance were similar to those obtained using traditional oven heating, even though the cross-linking time was significantly decreased from 1 h to 5 min. Besides the gate leakage current, the interface trap state density (Nit) was also calculated to describe the interface status between the gate insulator and the active layer. The lowest interface trap state density can be found in the device with the PVP gate insulator cross-linked by using the optimal MIH condition. Therefore, it is believed that the MIH scheme is a good candidate to cross-link the PVP gate insulator for organic thin-film transistor applications as a result of its features of rapid heating (5 min) and low-power microwave-irradiation (50 W).

Teflon/SiO2 Bilayer Passivation for Improving the Electrical Reliability of Oxide TFTs Fabricated Using a New Two-Photomask Self-Alignment Process.

This study proposes a two-photomask process for fabricating amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) that exhibit a self-aligned structure. The fabricated TFTs, which lack etching-stop (ES) layers, have undamaged a-IGZO active layers that facilitate superior performance. In addition, we demonstrate a bilayer passivation method that uses a polytetrafluoroethylene (Teflon) and SiO2 combination layer for improving the electrical reliability of the fabricated TFTs. Teflon was deposited as a buffer layer through thermal evaporation. The Teflon layer exhibited favorable compatibility with the underlying IGZO channel layer and effectively protected the a-IGZO TFTs from plasma damage during SiO2 deposition, resulting in a negligible initial performance drop in the a-IGZO TFTs. Compared with passivation-free a-IGZO TFTs, passivated TFTs exhibited superior stability even after 168 h of aging under ambient air at 95% relative humidity.

A Self-Aligned a-IGZO Thin-Film Transistor Using a New Two-Photo-Mask Process with a Continuous Etching Scheme.

Minimizing the parasitic capacitance and the number of photo-masks can improve operational speed and reduce fabrication costs. Therefore, in this study, a new two-photo-mask process is proposed that exhibits a self-aligned structure without an etching-stop layer. Combining the backside-ultraviolet (BUV) exposure and backside-lift-off (BLO) schemes can not only prevent the damage when etching the source/drain (S/D) electrodes but also reduce the number of photo-masks required during fabrication and minimize the parasitic capacitance with the decreasing of gate overlap length at same time. Compared with traditional fabrication processes, the proposed process yields that thin-film transistors (TFTs) exhibit comparable field-effect mobility (9.5 cm²/V·s), threshold voltage (3.39 V), and subthreshold swing (0.3 V/decade). The delay time of an inverter fabricated using the proposed process was considerably decreased.

Coupling technique for efficient interfacing between silica waveguides and planar photonic crystal circuits.

We describe a two-step-size tapered structure with one defect pair that can markedly enhance the coupling efficiency at the entrance and exit terminals of a planar photonic crystal (PPC) waveguide. PPC waveguides are composed of circular dielectric rods set in two-dimensional square lattices. On the basis of our simulations, we found that the optimized scheme maximizes the power transmission above 90% at a wavelength of 1.55 microm. Besides, one can control the central frequency for optical communications by determining this defect configuration in an optimization procedure. Moreover, by properly adjusting the defect radii in PPC tapers, one can use the PPC circuit as a good reflector.