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A low temperature solution-processed thin-film transistor (TFT) using zinc oxide (ZnO) film as an exposed sensing semiconductor channel was fabricated to detect and identify various solution solvents. The TFT devices would offer applications for low-cost, rapid and highly compatible water-soluble detection and could replace conventional silicon field effect transistors (FETs) as bio-sensors. In this work, we demonstrate the utility of the TFT ZnO channel to sense various liquids, such as polar solvents (ethanol), non-polar solvents (toluene) and deionized (DI) water, which were dropped and adsorbed onto the channel. It is discussed how different dielectric constants of polar/non-polar solvents and DI water were associated with various charge transport properties, demonstrating the main detection mechanisms of the thin-film transistor.

In this work, we used a sol-gel process to fabricate a ZnO-ZrO 2 -stacked resistive switching random access memory (ReRAM) device and investigated its switching mechanism. The Gibbs free energy in ZnO, which is higher than that in ZrO 2 , facilitates the oxidation and reduction reactions of filaments in the ZnO layer. The current-voltage (I-V) characteristics of the device revealed a forming-free operation because of nonlattice oxygen in the oxide layer. In addition, the device can operate under bipolar or unipolar conditions with a reset voltage of 0 to +2 V, indicating that in this device, Joule heating dominates at reset and the electric field dominates in the set process. Furthermore, the characteristics reveal why the fabricated device exhibits a greater discrete distribution phenomenon for the set voltage than for the reset voltage. These results will enable the fabrication of future ReRAM devices with double-layer oxide structures with improved characteristics.

A sol-gel method was applied with acetates as precursors under standard atmospheric conditions to fabricate ZnO semiconducting thin-films. We evaluated the performances of thin-film transistor (TFT) which has a ZnO active channel layer and the effects of stannum (Sn) doping on the threshold voltage of ZnO TFTs at a low temperature (300 ℃), which was compared with the performances of the undoped ZnO and stannum-doped zinc oxide (ZTO) TFT. The electrical characteristics of thin-films and TFTs doped with stannum concentrations of 0.3 mole ratio were examined; and reductions at the threshold voltage of 5.6 V were found. At 300 ℃, it was observed that the stannum-doped zinc oxide (ZTO) device has a mobility of 4.2 × 10 −4 cm 2 /V-s, a threshold voltage of 5.3 V, and an on/off current ratio of 10 4 .

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Aluminum oxide (AlO x ) and plasma immersion ion implantation (PIII) were studied in relation to passivated silicon heterojunction solar cells. When aluminum oxide (AlO x ) was deposited on the surface of a wafer; the electric field near the surface of wafer was enhanced; and the mobility of the carrier was improved; thus reducing carrier traps associated with dangling bonds. Using PIII enabled implanting nitrogen into the device to reduce dangling bonds and achieve the desired passivation effect. Depositing AlO x on the surface of a solar cell increased the short-circuit current density (J sc ); open-circuit voltage (V oc ); and conversion efficiency from 27.84 mA/cm 2 ; 0.52 V; and 8.97% to 29.34 mA/cm 2 ; 0.54 V; and 9.68%; respectively. After controlling the depth and concentration of nitrogen by modulating the PIII energy; the ideal PIII condition was determined to be 2 keV and 10 min. As a result; a 15.42% conversion efficiency was thus achieved; and the J sc ; V oc ; and fill factor were 37.78 mA/cm 2 ; 0.55 V; and 0.742; respectively.

Highly transparent zinc oxide (ZnO)-based thin-film transistors (TFTs) with gold nanoparticles (AuNPs) capable of detecting visible light were fabricated through spray pyrolysis on a fluorine-doped tin oxide substrate. The spray-deposited channel layer of ZnO had a thickness of approximately 15 nm, and the thickness exhibited a linear increase with an increasing number of sprays. Furthermore, the ZnO thin-film exhibited a markedly smoother channel layer with a significantly lower surface roughness of 1.84 nm when the substrate was 20 cm from the spray nozzle compared with when it was 10 cm away. Finally, a ZnO and Au-NP heterojunction nanohybrid structure using plasmonic energy detection as an electrical signal, constitutes an ideal combination for a visible-light photodetector. The ZnO-based TFTs convert localized surface plasmon energy into an electrical signal, thereby extending the wide band-gap of materials used for photodetectors to achieve visible-light wavelength detection. The photo-transistors demonstrate an elevated on-current with an increase of the AuNP density in the concentration of 1.26, 12.6, and 126 pM and reach values of 3.75, 5.18, and 9.79 × 10−7 A with applied gate and drain voltages. Moreover, the threshold voltage (Vth) also drifts to negative values as the AuNP density increases.