No abstract

An organic thin film back-gated transistor (OBGT) was fabricated and characterized. The gate electrode was printed on the back side of substrate, and the dielectric layer was omitted by substituting the dielectric layer with the polyimide (PI) film substrate. Roll-to-roll (R2R) gravure printing, doctor blading, and drop casting methods were used to fabricate the OBGT. The printed OBGT device shows better performance compared with an OTFT device based on dielectric layer of BaTiO3. Additionally, a calendering process enhanced the performance by a factor of 3 to 7 (mobility: 0.016 cm2/V·s, on/off ratio: 9.17×103). A bending test was conducted to confirm the flexibility and durability of the OBGT device. The results show the fabricated device endures 20000-cyclic motions. The realized OBGT device was successfully fabricated and working, which is meaningful for production engineering from the viewpoint of process development.

Cross-point array structure has attracted increasing attention for high-density ReRAM, owing to the development of ReRAM with promising scalability. Cross-point array of only resistors(1R) cannot function because of sneak current through unselected devices, which can be reduced by integrating resistive memory elements with bidirectional nonlinear selection devices(1S1R). Namely, the high value of Kw in ON states, which is the writing current @ Vwrite / the current @ 1/2Vwrite, was required in cross-point ReRAM memory industry. In this study, the high current density non-linear IV curve of Ovonic threshold switching(OTS) selection device based on Chalcogenide ZnTe was shown and the ALD HfO2 switching device has the linear properties of ON states and the compliance current of 100uA. In 1S1R unit cells based on ZnTe OTS selection device of low off current (< 400nA) and HfO2 switching device, excellent non-linear characteristics of ON states such as Kw of 522, Kr (reading current @Vread / current @ 1/2Vread) of 1430 and on/off ratio of 43 were shown. OTS behaviors with ZnTe film thickness, device area and annealing temperatures were investigated. Initial current during electro-forming process was decreased but OTS characteristics were not changed with increasing ZnTe thickness and decreasing device area. Initial current in electro-forming process and OTS characteristics at annealing temperature of below 200°C was not changed, but initial current and off current was rapidly increased and threshold voltage (Vth) in OTS was decreased at above 250°C because of Te diffusion in ZnTe film. To suppress the diffusion of Te atoms, the reactive N2during deposition which can improve the thermal stability of the chalcogenide glass was performed. And chemical compositions of ZnTe thin films were analyzed by Rutherford backscattering spectrometry(RBS). Also, crystallinity as a function of annealing temperature was investigated by Raman spectroscopy, X-ray diffraction (XRD) and plan-view transmission electron microscopy (TEM).

We propose a roll-to-roll process for vitamin D3 patch production. A solution of 7-dehydrocholesterol is applied to a plastic film by roll-to-roll slot-die coating and dried by a far-infrared lamp. Upon exposure to ultraviolet B irradiation, these films are converted to previtamin D3 films. After heat-treating the previtamin D3 film, high-performance liquid chromatography measurements are performed using commercial vitamin D3 as a standard sample. The results confirm that vitamin D3 can be produced by large-area coating and post-treatment processes. Specifically, 3.16 ± 0.746 mg of vitamin D3 is obtained through ultraviolet B irradiation and heat-treatment of 24.8 ± 1.44 mg of coated 7-dehydrocholesterol.