Shui-Jinn Wang

Bio: Shui-Jinn Wang is an academic researcher from National Cheng Kung University. The author has contributed to research in topics: Light-emitting diode & Thin-film transistor. The author has an hindex of 22, co-authored 178 publications receiving 1656 citations.

Use of patterned laser liftoff process and electroplating nickel layer for the fabrication of vertical-structured GaN-based light-emitting diodes

Abstract: The fabrication process and performance characteristics of a vertical-structured GaN-based light-emitting diode (VM-LED) employing nickel electroplating and patterned laser liftoff techniques are presented. As compared to regular LED, the forward voltage drop of the VM-LED at 20–80 mA is about 10%–21% lower, while the light output power (Lop) is more than twice in magnitude. Especially, the Lop exhibits no saturation or degradation at an injection current up to 520 mA which is about 4.3 times higher than that of the regular one. Substantial improvements in the VM-LEDs performances are mainly attributed to the use of metallic substrate which results in less current crowding, larger effective area, and higher thermal conductivity.

Enhanced sensing performance of relative humidity sensors using laterally grown ZnO nanosheets

Abstract: This study investigates the effectiveness of using laterally oriented zinc oxide (ZnO) nanosheets (NSs) grown by the hydrothermal growth (HTG) method for relative humidity (RH) sensing at room temperature (RT). A sensing response (R12%/R96%) at RT of as high as 220, good sensing linearity in the range of 12–96% RH, a fast sensing response time of as low as 600 s, and a recovery time of 3 s are achieved. Compared to conventional ZnO-nanowire-based humidity sensors, a 100-fold improvement in the sensing response at RT was obtained, which is mainly attributed to the ZnO NSs having a much higher surface-to-volume ratio and a porous-like surface.

Enhanced sensing performance of relative humidity sensors using laterally grown ZnO nanosheets

Abstract: This study investigates the effectiveness of using laterally oriented zinc oxide (ZnO) nanosheets (NSs) grown by the hydrothermal growth (HTG) method for relative humidity (RH) sensing at room temperature (RT). A sensing response (R12%/R96%) at RT of as high as 220, good sensing linearity in the range of 12–96% RH, a fast sensing response time of as low as 600 s, and a recovery time of 3 s are achieved. Compared to conventional ZnO-nanowire-based humidity sensors, a 100-fold improvement in the sensing response at RT was obtained, which is mainly attributed to the ZnO NSs having a much higher surface-to-volume ratio and a porous-like surface.

Low-Voltage-Driven Flexible InGaZnO Thin-Film Transistor With Small Subthreshold Swing

Abstract: A flexible thin-film transistor (TFT) was made by integrating a high- HfLaO gate dielectric and an amorphous-InGaZnO (a-IGZO) active layer on a polyimide substrate. This flexible HfLaO/a-IGZO TFT exhibits a low threshold voltage of 0.1 V, a small subthreshold swing of 0.18 V/dec, a high maximum saturation mobility of 22.1 cm2/V s, and an acceptable on/off current ratio of 2 × 10-5. The low threshold voltage and small subthreshold swing allow the device to operate at 1.5 V for low-power applications, which should enable significant future progress in energy efficiency.

Organic light-emitting diode on indium zinc oxide film prepared by ion assisted deposition dc sputtering system

Abstract: In this letter, high-quality indium zinc oxide (IZO) films (60–220 nm) were first grown on hardness poly-carbonate substrate by ion-assisted deposition (IAD) dc magnetron sputtering without a post deposition annealing treatment. The electrical, optical, and structural properties of these films were investigated as a function of film thickness. IAD dc magnetron sputtering provides very uniform IZO films with high transparency (⩾85% in 550 nm spectrum) and low electrical resistivity ( 3×10 −4 Ω cm). The Hall mobility and carrier density for a 120-nm-thick film at 100 W are 12 cm 2 /V s and 2.5×10 21 cm −3 , respectively. The IZO films grown at low temperature by IAD dc magnetron sputtering were used for the organic light-emitting devices (OLEDs) as transparent anode. Under a current density of 100 mA/cm 2 , the developed OLEDs show an excellent efficiency (12 V turn-on voltage) and a luminance of 1200 cd/m 2 in average, which is better than that measured with commercial ITO anodes and suitable for the electro-optical application.

Oxide Semiconductor Thin‐Film Transistors: A Review of Recent Advances

Abstract: Transparent electronics is today one of the most advanced topics for a wide range of device applications. The key components are wide bandgap semiconductors, where oxides of different origins play an important role, not only as passive component but also as active component, similar to what is observed in conventional semiconductors like silicon. Transparent electronics has gained special attention during the last few years and is today established as one of the most promising technologies for leading the next generation of flat panel display due to its excellent electronic performance. In this paper the recent progress in n- and p-type oxide based thin-film transistors (TFT) is reviewed, with special emphasis on solution-processed and p-type, and the major milestones already achieved with this emerging and very promising technology are summarizeed. After a short introduction where the main advantages of these semiconductors are presented, as well as the industry expectations, the beautiful history of TFTs is revisited, including the main landmarks in the last 80 years, finishing by referring to some papers that have played an important role in shaping transparent electronics. Then, an overview is presented of state of the art n-type TFTs processed by physical vapour deposition methods, and finally one of the most exciting, promising, and low cost but powerful technologies is discussed: solution-processed oxide TFTs. Moreover, a more detailed focus analysis will be given concerning p-type oxide TFTs, mainly centred on two of the most promising semiconductor candidates: copper oxide and tin oxide. The most recent data related to the production of complementary metal oxide semiconductor (CMOS) devices based on n- and p-type oxide TFT is also be presented. The last topic of this review is devoted to some emerging applications, finalizing with the main conclusions. Related work that originated at CENIMAT|I3N during the last six years is included in more detail, which has led to the fabrication of high performance n- and p-type oxide transistors as well as the fabrication of CMOS devices with and on paper.

Light-emitting diodes

Abstract: Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

Zinc Oxide Nanostructures for NO2 Gas–Sensor Applications: A Review

Abstract: Because of the interesting and multifunctional properties, recently, ZnO nanostructures are considered as excellent material for fabrication of highly sensitive and selective gas sensors. Thus, ZnO nanomaterials are widely used to fabricate efficient gas sensors for the detection of various hazardous and toxic gases. The presented review article is focusing on the recent developments of NO2 gas sensors based on ZnO nanomaterials. The review presents the general introduction of some metal oxide nanomaterials for gas sensing application and finally focusing on the structure of ZnO and its gas sensing mechanisms. Basic gas sensing characteristics such as gas response, response time, recovery time, selectivity, detection limit, stability and recyclability, etc are also discussed in this article. Further, the utilization of various ZnO nanomaterials such as nanorods, nanowires, nano-micro flowers, quantum dots, thin films and nanosheets, etc for the fabrication of NO2 gas sensors are also presented. Moreover, various factors such as NO2 concentrations, annealing temperature, ZnO morphologies and particle sizes, relative humidity, operating temperatures which are affecting the NO2 gas sensing properties are discussed in this review. Finally, the review article is concluded and future directions are presented.

Vertically Aligned WO3 Nanowire Arrays Grown Directly on Transparent Conducting Oxide Coated Glass: Synthesis and Photoelectrochemical Properties

Abstract: Photocorrosion stable WO3 nanowire arrays are synthesized by a solvothermal technique on fluorine-doped tin oxide coated glass. WO3 morphologies of hexagonal and monoclinic structure, ranging from nanowire to nanoflake arrays, are tailored by adjusting solution composition with growth along the (001) direction. Photoelectrochemical measurements of illustrative films show incident photon-to-current conversion efficiencies higher than 60% at 400 nm with a photocurrent of 1.43 mA/cm2 under AM 1.5G illumination. Our solvothermal film growth technique offers an exciting opportunity for growth of one-dimensional metal oxide nanostructures with practical application in photoelectrochemical energy conversion.