In this study, the electrical properties of zinc oxide (ZnO) thin-film transistors (TFTs) based on oxide semiconductors were analyzed. As interest in next-generation transparent and flexible displays grows, ZnO, which offers high field-effect mobility and transparency, has emerged as a promising material to overcome the limitations of amorphous silicon (a-Si)-based TFTs. ZnO has a wide bandgap and optical transparency and can be deposited on various substrates at low temperatures, making it a suitable channel material for future display devices. In this study, ZnO TFTs were fabricated with an inverted staggered structure using a p⁺⁺ Si wafer coated with SiO₂ as the substrate. The ZnO channel layer was deposited by RF magnetron sputtering, and the ITO source/drain electrodes were formed using an e-beam evaporator. The electrical characteristics was evaluated using Keithley 4200A-SCS parameter analyzer. Mobility, On/Off ratio, and subthreshold swing (SS) were calculated from the measurements.

This study introduces a new investigation report on the microstructural and electrical property changes of ZnO-Zn₂BiVO₆-Mn₃O₄ (ZZMn), where 0.33 mol% of Mn₃O₄ and 0.5 mol% of Zn₂BiVO₆ were added to ZnO (99.17 mol%) as liquid phase sintering aids. Zn₂BiVO₆ contributes to the decrease of sintering temperatures by up to 800℃, and segregates its particles at the grain boundary, while Mn₃O₄ enhances α, the nonlinear coefficient, of varistor properties up to α＝62. In comparison, when the sintering temperature is increased from 800℃ to 1,000℃, the resistivity of ZnO grains decreases from 0.34 Ωcm to 0.16 Ωcm, and the varistor property degrades. Oxygen vacancy (V_o^·) (P1, 0.33~0.36 eV) is formed as a dominant defect. Two different kinds of grain boundary activation energies of P2 (0.51~0.70 eV) and P3 (0.70~0.93 eV) are formed according to different sintering temperatures, which are tentatively attributed to be ZnO/Zn₂BiVO₆-rich interface and ZnO/ZnO interface, respectively. Accordingly, this study introduces a progressive method of manufacturing ZnO chip varistors by way of sintering ZZMn-based varistor under 900℃. However, to procure a higher reliability, an in-depth study on the multi-component varistors with double-layer grain boundaries should be executed.

The carbon nanotube / poly-vinylidene fluoride (CNT/PVDF) composite films for the nano-generator devices were fabricated by spray coating method using the CNT/PVDF solution, which was prepared by adding PVDF pellets into the CNT dispersed N-Methyl-2-pyrroli-done (NMP) solution. The flexible CNT/PVDF composite films were investigated by the scanning electron microscopy, which revealed that the CNTs were uniformly dispersed in the PVDF matrix and thickness of the films was approximately 20 jim. Fourier transform infra-red spectra were used to investigate crystal structure of the as-spray-coated CNT/PVDF films, and we found that they revealed extremely large portion of the f3 phase PVDF. The capacitance of the CNT/PVDF films increased by adding CNTs into the PVDF matrix, and finally saturated. However, the resistance didn`t show any saturation effect in the CNT concentration range of 0- 4 wt%. Finally, the resulting nano-generator devices revealed reasonable current output after given mechanical stress.

In this study, the W-interconnected dye-sensitized solar cell (DSSC) modules composed of a number of rectangular cells connected in series were investigated, where neighboring cells are processed in reverse. The DSSC modules, a module of dimension about 200 mm × 200 mm, were fabricated with different working electrode width ranging from 5 mm to 21 mm. The short-circuit current of the module increased as the working electrode width increased. Whereas, the decrease in the working electrode width resulted in the increase of the conversion energy efficiency, fill factor, and open-circuit voltage, which is explained by the fact that the possibility that electrons are recombined along their path on the transparent conductive oxide substrate decreases. The module with the conversion energy efficiency of 3.59% was obtained with the working electrode width of 5 mm.

In this study we aims to examine the effects of Co3O4 and NiO doping on the defects and electrical properties in ZnO-Bi2O3-Sb2O3 (Sb/Bi=0.5) varistors. It seemed to form □(0.20 eV) and □(0.33 eV) as dominant defects in Co and Ni co-doped ZBS system, however only □appeared in Co- or Ni-doped ZBS. Even though the same defects it was different in capacitance (1.5∼4.5 nF) and resistance (0.3∼9.5 kΩ). The varistor characteristics were improved with Co and Co+Ni doping (non-linear coefficient, α= 36 and 29, relatively) in ZBS. The various parameters (Nd= 1.43∼2.33×1017 cm-3, Nt=1.40∼ 2.28×1012 cm-2, Φb= 1.76∼2.37 V, W= 98∼118 nm) calculated from the C-V characteristics in our systems did not depend greatly on the type of dopant, which were in the range of a typical ZnO varistors. It should be derived a improved C-V equation carefully for more reliable parameters because the variation of the varistor capacitance as a function of the applied dc voltage is depend on the defect, frequency, and temperature.