Browsing by Author "Ho, Po-Ching"

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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
Cu(In,Ga)Se-2 thin films preparation from CuGa-In metallic alloy and Se thin film by atmosphere pressure plasma deposition system
(2012)
Chang, Kow-Ming
;
Ho, Po-Ching
;
Yang, Kuo-Hui
;
Wu, Shen-Bin
;
Liu, Chi-Hung
An atmosphere pressure plasma (APP) deposition system with dielectric barrier discharge (DBD) is proposed for deposition selenium thin films on CuGa-In metallic precursors and transformed into Cu(In,Ga)Se-2 (CIGS) thin films by rapid thermal process (RTP). Morphologies and thicknesses of selenium thin films deposited on In/CuGa/Mo/SLG can be affected by plasma power which also has impact on crystallinity of CIGS absorber. With the increase in plasma power, CIGS grains tend to distribute non-uniformly. Plasma power of 100W has the smallest FWHM of the main peak (112). Insufficient selenium incorporation into precursors result in undesired phases such as Cu3Se2, Cu2Se and separation phase, CuGaSe2 compound. Compositions of optimal selenized CIGS thin film deposited by scanning 180times are Cu/(In+Ga) = 1.03 and Ga/(In+Ga) = 0.24.
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.
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.
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.