Browsing by Author "Yu, Shu-Hung"

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Cost-Effective and Self-Textured Gallium-Doped Zinc Oxide Front Contacts for Hydrogenated Amorphous Silicon Thin-Film Solar Cells
(2013-02-01)
Yu, Shu-Hung
;
Ho, Po-Ching
;
Lee, Chia-Ling
;
Bi, Chien-Chung
;
Yeh, Chih-Hung
We adopt a economical and original method to fabricate self-textured gallium-doped zinc oxide (GZO) front contacts for hydrogenated amorphous silicon (a-Si: H) single-junction solar cells. This technique involves an atmospheric-pressure plasma jet (APPJ) and a dc sputtering process. The electro-optical characteristics of the textured GZO films are mainly controlled by the haze of organosilicon underlayers deposited by the APPJ. The films exhibit an average optical transmittance of about 80% and resistivity below 9.91 x 10(-4) Omega cm. Moreover, compared with flat solar cells, textured cells fabricated on moderate GZO front contacts show 7.9 and 10.9% enhancements in conversion efficiency and short-circuit current density, respectively. (C) 2013 The Japan Society of Applied Physics
Double-Pattern Textured ZnO:Ga Thin Films Fabricated by an APPJ and an DC Sputtering
(2012)
Yu, Shu-Hung
;
Ho, Po-Ching
;
Yang, Teng-Wei
;
Bi, Chien-Chung
;
Yeh, Chih-Hung
Here, double-pattern textured gallium doped zinc oxide (GZO) films were achieved by inserting organosilicon underlayers deposited from an atmospheric pressure plasma jet (APPJ) between sputtered GZO films and glass substrates. The electro-optical characteristics of the textured GZO films were controlled by the haze of organosilicon underlayers. All GZO films were thermally annealed in high vacuum to improve film quality. Post-annealed textured GZO films exhibited an average optical transmittance of about 80% in a wide range. Hall measurements showed Hall mobility above 26 cm(2)/V-s, carrier concentration around 2.4 x 10(20) cm(-3) and resistivity below 9.91 x 10(-4) Omega-cm. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.003203ssl] All rights reserved.
Effects of growth temperature on InN/GaN nanodots grown by metal organic chemical vapor deposition
(2008-05-15)
Chang, Wen-Hao
;
Ke, Wen-Cheng
;
Yu, Shu-Hung
;
Lee, Lin
;
Chen, Ching-Yu
InN nanodots grown on GaN by metal organic chemical vapor deposition using conventional growth mode as well as flow-rate modulation epitaxy at various growth temperatures (550-730 degrees C) were investigated. We found that different precursor injection schemes together with the effect of growth temperatures greatly influenced the surface morphology of InN nanodots and their photoluminescence (PL) properties. The sample grown at around 650 degrees C showed the highest growth rate. For samples grown at higher temperatures, the residual carrier concentration was reduced and the PL efficiency was improved. Furthermore, we found that the growth of InN nanodots is still sustainable even at a temperature higher than 700 degrees C while retaining their optical quality. (c) 2008 American Institute of Physics.
Flexible InGaZnO TFTs with Stacked GeO2/TiO2 Gate Dielectrics
(2013)
Hsu, Hsiao-Hsuan
;
Chang, Chun-Yen
;
Cheng, Chun-Hu
;
Yu, Shu-Hung
;
Su, Ching-Yuan
We reported an amorphous InGaZnO thin-film transistor using stacked gate dielectrics of GeO2/TiO2 on flexible polycarbonate substrate. The flexible TFT showed a low threshold voltage of 2.2 V, small sub-threshold swing of 256 mV/decade, an field effect mobility of 4 cm(2)/Vs, and a good I-on/I-off ratio of 3.7x10(5). The flexible TFT with low operation voltage and high drive current could be attributed to the combined effect of flat plastic substrate, large band-gap GeO2 and higher-kappa TiO2.
Fully room-temperature IGZO thin film transistors adopting stacked gate dielectrics on flexible polycarbonate substrate
(2013-11-01)
Hsu, Hsiao-Hsuan
;
Chang, Chun-Yen
;
Cheng, Chun-Hu
;
Yu, Shu-Hung
;
Su, Ching-Yuan
This study demonstrates the feasibility of producing an InGaZnO thin-film transistor (TFT) using a high-kappa germanium oxide (GeO2)/titanium oxide (TiO2)/GeO2 gate stack on a flexible polycarbonate substrate. The flexible TFT exhibited a small sub-threshold swing of 0.132 V/decade, an acceptable field effect mobility of 8 cm(2)/(V s), and a robust I-on/I-off ratio of 2.4 x 10(7). The improved device performance can be attributed to the combined effect of high-kappa TiO2 and the large band gap of GeO2 that exhibits a tendency to remain in a Ge4+ oxidation state at room temperature. (C) 2013 Elsevier Ltd. All rights reserved.
High Improvement in Conversion Efficiency of mu c-SiGe Thin-Film Solar Cells with Field-Enhancement Layers
(2012)
Yu, Shu-Hung
;
Lin, Wei
;
Chen, Yu-Hung
;
Chang, Chun-Yen
;
電子工程學系及電子研究所
The improved performance for hydrogenated microcrystalline silicon-germanium (mu c-Si1-xGex:H, x similar to 0.1) p-i-n single solar cells with hydrogenated microcrystalline silicon (mu c-Si:H) field-enhancement layers (FELs) is demonstrated for the first time. The fill factor (FF) and conversion efficiency (eta) increase by about 19% and 28% when the thickness of the mu c-Si FEL is increased from 0 to 200 nm, it is attributed to the longer hole life-time and enhanced electric field in the mu c-Si0.9Ge0.1:H layer. Therefore, we can successfully manufacture high-performance mu c-SiGe:H solar cells with the thickness of absorbers smaller than 1 mu m by conducting FELs. Moreover, the simulation tool is used to simulate the current-voltage (J-V) curve, thus we can investigate the carrier transport in the absorber of mu c-Si0.9Ge0.1:H solar cells with different EFLs.
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.