Browsing by Author "Chang, Chia-Chiang"

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Characteristics of IGZO TFT Prepared by Atmospheric Pressure Plasma Jet Using PE-ALD Al2O3 Gate Dielectric
(2012-04-01)
Wu, Chien-Hung
;
Chang, Kow-Ming
;
Huang, Sung-Hung
;
Deng, I-Chung
;
Wu, Chin-Jyi
This letter proposes a novel atmospheric pressure plasma jet (APPJ) method for indium-gallium-zinc-oxide (IGZO) deposition and use of the plasma-enhanced atomic layer deposition (PE-ALD) Al2O3 as gate dielectric. A nonvacuum and simple APPJ system was demonstrated for channel material deposition. High-transmittance nanocrystalline IGZO thin films were obtained. Excellent electrical characteristics were achieved, including a low V-T of 0.71 V, a small subthreshold swing of 276 mV/dec, a mobility of 8.39 cm(2)/(V . s), and a large I-on/I-off ratio of 1 x 10(8).
Enhancement of the light-scattering ability of Ga-doped ZnO thin films using SiOx nano-films prepared by atmospheric pressure plasma deposition system
(2013-12-02)
Chang, Kow-Ming
;
Ho, Po-Ching
;
Ariyarit, Atthaporn
;
Yang, Kuo-Hui
;
Hsu, Jui-Mei
To enhance the light-trapping qualities of silicon thin-film solar cells, the use of transparent conductive oxide with high haze and high conductivity is essential. This study investigated an eco-friendly technique that used bilayer Ga-doped zinc oxide/SiOx films prepared with an atmospheric pressure plasma jet to achieve high haze and low resistivity. A minimum resistivity of 6.00 x 10(-4) Omega.cm was achieved at 8 at.% gallium doping. Examination of X-ray diffraction spectra showed that increased film thickness led to increased carrier concentration in GZO bilayers. The optimal bilayer GZO film achieved considerably higher haze values in the visible and NIR regions, compared with Asahi U-type fluorine doped tin oxide. (C) 2013 Elsevier B. V. All rights reserved.
Structural and optoelectronic properties of GZO/SiOx bilayer films by atmosphere pressure plasma jet
(2012)
Chang, Kow-Ming
;
Ho, Po-Ching
;
Wu, Chi-Wei
;
Wu, Chin-Jyi
;
Chang, Chia-Chiang
Using simple technique to obtain high haze and high conductivity TCO films to enhance optical absorption for silicon thin film solar cell is important. The bilayer GZO film of high haze and low resistivity is achieved by atmosphere pressure plasma jet (APPJ). Thickness of bilayer GZO film was thinner than Asahi-U type FTO film and this result indicated that the APPJ deposition technique has lower material comsumption. The minimum resistivity of 6.00x10(-4) was achieved at 8 at% gallium doping. Xray diffraction spectrum showed that an increase in scanning times led to an increase in crystallinity of bilayer GZO films. The bilayer GZO film has much higher haze value in the visible and NIR regions as compared to Asahi U-type FTO film.
The Effect of Different Carrier Gases and Channel Thicknesses on the Characteristics of ZnO TFTs Prepared by Atmospheric Pressure Plasma Jet
(2011)
Chang, Kow-Ming
;
Huang, Sung-Hung
;
Chi, Chia-Wei
;
Wu, Chin-Jyi
;
Lin, Je-Wei
Thin film transistors (TFTs) with a ZnO channel layer deposited by atmospheric pressure plasma jet (APPJ) were demonstrated. ZnO channel layers were fabricated with a non-vacuum and low-temperature process (100 degrees C). The effects of different carrier gases (nitrogen gas and compressed dry air) and channel thickness on the characteristics of ZnO TFTs were investigated. Reactive oxygen species can effectively repair the oxygen vacancies result in a low leakage current. By reducing the channel thickness, the undesired source to drain current flow can be eliminated. By using CDA as a carrier gas and reducing the channel thickness, a subthreshold swing of 3.75 V/decade, a field-effect mobility of 3.49 cm(2)/Vs and a Ion/Ioff current ratio of 4.08x10(7) were obtained.
The effect of oxygen species on the ZnO TFT prepared by atmosphere pressure plasma jet
(2012)
Wu, Chien-Hung
;
Chang, Kow-Ming
;
Huang, Sung-Hung
;
Deng, I-Chung
;
Chi, Chia-Wei
Bottom-gate thin-film transistors (TFTs) were fabricated with ZnO channel layer deposited by atmospheric pressure plasma jet (APPJ). The effect of oxygen partial pressure on the ZnO TFT was investigated. The ZnO thin films were deposited at 100 degrees C, and oxygen gas was incorporated into plasma gas (N-2) in the percentage of 0%-1% (O-2/N-2+O-2). Reactive oxygen species could repair the oxygen vacancies during deposition, and the switching behavior was improved effectively. With increasing oxygen partial pressure, the ZnO thin films exhibited a more random orientation. By incorporating 0.69% O-2 into plasma gas, a threshold voltage of 26.7 V, a subthreshold swing of 3.89 V/decade, a field-effect mobility of 2.38 cm(2)/Vs and an I-on/I-off current ratio of 4.63x10(9) were obtained.
The effect of thermal annealing on the properties of IGZO TFT prepared by atmospheric pressure plasma jet
(2012)
Wu, Chien-Hung
;
Chang, Kow-Ming
;
Huang, Sung-Hung
;
Deng, I-Chung
;
Wu, Chin-Jyi
We fabricated bottom gate TFTs with IGZO channel layer deposited by atmospheric pressure plasma jet (APPJ). The effect of thermal annealing on the properties of IGZO TFTs was studied. After post annealing, the IGZO thin films showed a smooth and dense structure. The transistors annealed at 300 degrees C showed clear switching behavior with a negative threshold voltage of -0.571 V and a mobility of 2.6 cm(2)/V-s. After 500 degrees C post annealing, IGZO thin film showed an amorphous-like phase and the average transmittance is more than 80% in the visible range. Good electrical characteristics were achieved, including a threshold voltage of 6.74V, a subthreshold swing of 1.54 V/dec, a mobility of 10.31 cm(2)/V-s and a large I-on/I-off ratio of 3.28x10(8).
Transparent conductive indium-doped zinc oxide films prepared by atmospheric pressure plasma jet
(2011-05-31)
Chang, Kow-Ming
;
Huang, Sung-Hung
;
Wu, Chin-Jyi
;
Lin, Wei-Li
;
Chen, Wei-Chiang
Atmospheric-pressure plasma processing has attracted much interest for industrial applications due to its low cost, high processing speed and simple system. In this study, atmospheric-pressure plasma jet technique was developed to deposit indium-doped zinc oxide films. The inorganic metal salts of zinc nitrate and indium nitrate were used as precursors for Zn ions and In ions, respectively. The effect of different indium doping concentration on the morphological, structural, electrical and optical properties of the films was investigated. Grazing incidence X-ray diffraction results show that the deposited films with a preferred (002) orientation. The lowest resistivity of 1.8 x 10(-3) Omega cm was achieved with the 8 at.% indium-doped solution at the substrate temperature of 200 degrees C in open air, and average transmittance in the visible region was more than 80%. (C) 2011 Elsevier B.V. All rights reserved.
Using SiOx nano-films to enhance GZO Thin films properties as front electrodes of a-Si solar cells
(2013-07-01)
Chang, Kow-Ming
;
Ho, Po-Ching
;
Yu, Shu-Hung
;
Hsu, Jui-Mei
;
Yang, Kuo-Hui
One of the essential applications of transparent conductive oxides is as front electrodes for superstrate silicon thin-film solar cells. Textured TCO thin films can improve absorption of sunlight for an a-Si:H absorber during a single optical path. In this study, high-haze and low-resistivity bilayer GZO/SiOx thin films prepared using an atmospheric pressure plasma jet (APPJ) deposition technique and dc magnetron sputtering. The silicon subdioxide nano-film plays an important role in controlling the haze value of subsequent deposited GZO thin films. The bilayer GZO/SiOx (90 sccm) sample has the highest haze value (22.30%), the lowest resistivity (8.98 x 10(-4) Omega cm), and reaches a maximum cell efficiency of 6.85% (enhanced by approximately 19% compared to a sample of non-textured GZO). (c) 2013 Elsevier B.V. All rights reserved.