Browsing by Author "Tsai, Chuang-Chuang"

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A Direct-View Backlight With UV Excited Trichromatic Phosphor Conversion Film
(2010-04-01)
Huang, Hsin-Tao
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Tsai, Chuang-Chuang
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Huang, Yi-Pai
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光電工程學系
;
顯示科技研究所
This work presents a novel ultraviolet (UV) excited flat lighting (UFL) system consisting of remote phosphor converter (RPC) for liquid-crystal display (LCD) backlight applications. A trichromatic RPC is excited using 254 nm UV lamps to achieve a slim, high color saturation and high luminance backlight. Experimental results indicate that the module thickness reduces to 14.5 mm, along with a high color saturation (92% of the NTSC standard) as well as a high luminance (573 cd/m(2)) when applied to large sized display (42-inch). Additionally, the proposed UFL backlight configuration has already been certified by a lifetime test to ensure the feasibility of proposed system in mass production.
Achieving High Field-Effect Mobility in Amorphous Indium-Gallium-Zinc Oxide by Capping a Strong Reduction Layer
(2012-07-10)
Zan, Hsiao-Wen
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Yeh, Chun-Cheng
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Meng, Hsin-Fei
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Tsai, Chuang-Chuang
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Chen, Liang-Hao
Amorphous indium-gallium-zinc-oxide visible-light phototransistor with a polymeric light absorption layer
(2010-11-15)
Zan, Hsiao-Wen
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Chen, Wei-Tsung
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Hsueh, Hsiu-Wen
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Kao, Shih-Chin
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Ku, Ming-Che
This work demonstrates a real-time visible-light phototransistor comprised of a wide-band-gap amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) and a narrow-band-gap polymeric capping layer. The capping layer and the IGZO layer form a p-n junction diode. The p-n junction absorbs visible light and consequently injects electrons into the IGZO layer, which in turn affects the body voltage as well as the threshold voltage of a-IGZO TFT. The hysteresis behavior due to the charges at IGZO back interface is also discussed. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3517506]
Amorphous indium-gallium-zinc-oxide visible-light phototransistor with a polymeric light absorption layer
(2010-11-15)
Zan, Hsiao-Wen
;
Chen, Wei-Tsung
;
Hsueh, Hsiu-Wen
;
Kao, Shih-Chin
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Ku, Ming-Che
This work demonstrates a real-time visible-light phototransistor comprised of a wide-band-gap amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) and a narrow-band-gap polymeric capping layer. The capping layer and the IGZO layer form a p-n junction diode. The p-n junction absorbs visible light and consequently injects electrons into the IGZO layer, which in turn affects the body voltage as well as the threshold voltage of a-IGZO TFT. The hysteresis behavior due to the charges at IGZO back interface is also discussed. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3517506]
Application of Porous a-Si:H Passivation Layer Deposited Using Si2H6 Precursor in Silicon Heterojunction Solar Cells
(2018-01-01)
Chen, Po-Wei
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Chen, Pei-Ling
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Hsu, Hung-Jung
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Matsui, Takuya
;
Sai, Hitoshi
The improved silicon heterojunction solar cell efficiency by employing porous a-Si:H passivation layer deposited using Si2H6 precursor is presented. By introducing Si2H6 precursor into the commonly-used SiH4 plasma, it is demonstrated that the porosity of a-Si:H passivation layer can be increased significantly. A stack of the porous a-Si:H passivation layer with overlying dense a-Si:H capping layer preserves excellent interface passivation even after doped layer deposition. In the finished solar cell, improvements in Voc from 0.691 to 0.714 V and efficiency from 20.0 to 21.0% were obtained as a consequence of using porous a-Si:H passivation layer deposited under high Si2H6 concentration.
Applications of mu c-SiOx:H as integrated n-layer and back transparent conductive oxide for a-Si:H/mu c-Si:H tandem cells
(2014-05-01)
Liang, Shin-Wei
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Huang, Yen-Tang
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Hsu, Hung-Jung
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Hsu, Cheng-Hang
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Tsai, Chuang-Chuang
We have prepared n-type hydrogenated microcrystalline silicon oxide [mu c-SiOx:H(n)] films with oxygen contents from 0 to 37.3 at. % by varying the CO2-to-SiH4 flow ratio in a plasma-enhanced chemical vapor deposition (PECVD) system. By using mu c-SiOx:H(n) as an effective replacement for integrated mu c-Si:H(n) and indium-tin oxide (ITO), mu c-Si:H single-junction and a-Si:H/mu c-Si:H tandem cells exhibited significantly improved efficiencies of 6.35 and 10.53%, respectively. The improvement of the single-junction and tandem cells mainly arose from the enhancement of long-wavelength optical absorption in mu c-Si:H absorbers, which was confirmed by a quantum efficiency instrument showing a markedly enhanced spectral response at wavelengths from 600 to 1100 nm. Moreover, all the PECVD processes, except the metal contact, had an advantage of in situ deposition without breaking vacuum, thereby minimizing contamination of the interface. The simplified cell fabrication can enhance the fill factor, which will benefit industrial production. (C) 2014 The Japan Society of Applied Physics
Conformal phosphor coating using pulsed spray to reduce color deviation of white LEDs
(2010-06-21)
Huang, Hsin-Tao
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Tsai, Chuang-Chuang
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Huang, Yi-Pai
;
光電工程學系
;
顯示科技研究所
This work presents a novel "pulsed spray (PS)" process for the coating of yellow YAG:Ce3+ phosphor on blue InGaN-based light emitting diodes (LEDs). To coat a phosphor layer of high quality on an LED chip surface, the PS approach is used and studied because of the uniform color distribution, providing a wide range of color temperatures. This PS coating approach applies phosphor by exploiting mechanical principles without risk of chemical pollution. Additionally, it can be applied to wire-bonded LEDs and an array of LED chips on a substrate to fabricate a large-area, planar illumination system of high optical quality, which is easy to manufacture. (C) 2010 Optical Society of America
Development of Hydrogenated Microcrystalline Silicon-Germanium Alloys for Improving Long-Wavelength Absorption in Si-Based Thin-Film Solar Cells
(2014)
Huang, Yen-Tang
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Hsu, Hung-Jung
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Liang, Shin-Wei
;
Hsu, Cheng-Hang
;
Tsai, Chuang-Chuang
Hydrogenated microcrystalline silicon-germanium (mu c-Si1-xGex:H) alloys were developed for application in Si-based thin-film solar cells. The effects of the germane concentration (R-GeH4) and the hydrogen ratio (R-H2) on the mu c-Si1-xGex:H alloys and the corresponding single-junction thin-film solar cells were studied. The behaviors of Ge incorporation in a-Si1-xGex:H and mu c-Si1-xGex:H were also compared. Similar to a-Si1-xGex:H, the preferential Ge incorporation was observed in mu c-Si1-xGex:H. Moreover, a higher R-H2 significantly promoted Ge incorporation for a-Si1-xGex: H, while the Ge content was not affected by R-H2 in mu c-Si1-xGex:H growth. Furthermore, to eliminate the crystallization effect, the 0.9 mu m thick absorbers with a similar crystalline volume fraction were applied. With the increasing R-GeH4, the accompanied increase in Ge content of mu c-Si1-xGex:H narrowed the bandgap and markedly enhanced the long-wavelength absorption. However, the bias-dependent EQE measurement revealed that too much Ge incorporation in absorber deteriorated carrier collection and cell performance. With the optimization of R-H2 and R-GeH4, the single-junction mu c-Si1-xGex:H cell achieved an efficiency of 5.48%, corresponding to the crystalline volume fraction of 50.5% and Ge content of 13.2 at.%. Compared to mu c-Si:H cell, the external quantum efficiency at 800nm had a relative increase by 33.1%.
Development of plasma-enhanced chemical vapor deposition microcrystalline silicon oxide as a replacement for N-type or back transparent conducting oxide layers in amorphous silicon single-junction solar cells
(2014-07-01)
Liang, Shin-Wei
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Hsu, Hung-Jung
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Hsu, Cheng-Hang
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Tsai, Chuang-Chuang
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光電工程學系
The n-type hydrogenated microcrystalline silicon oxide (mu c-SiOx:H(n)) thin films with varied electrical and optical properties were prepared. We employed mu c-SiOx:H(n) as a replacement for n-type hydrogenated amorphous silicon (a-Si: H(n)) or back transparent conducting oxide (TCO) layers in hydrogenated amorphous silicon (a-Si:H) single-junction solar cells. Compared to the standard cell with a-Si:H(n)/ITO/Ag back reflecting structure, the cell using a-Si: H(n)/mu c-SiOx:H(n)/Ag or mu c-SiOx:H(n)/Ag showed a similar or even better performance. This improvement of cell performance mainly arose from the increased short-circuit current density (J(SC)) that originated from the increased long wavelength (580-660 nm) absorption in the absorber confirmed by the quantum efficiency measurement. The "all plasma-enhanced chemical vapor deposition" (if the front TCO and metal contact are disregarded) process without TCO (indium tin oxide, ITO) sputtering can simplify the fabrication and result in better interface quality. Compared to the standard cell, the conversion efficiency of a-Si:H cells using an 80 nm thick mu c-SiOx:H(n)/Ag back reflecting structure was enhanced from 9.32% to 9.84%, with V-OC = 0.90 V, J(SC) = 14.84 mA/cm(2), and FF = 73.7%.
Development of Wider Bandgap n-type a-SiOx:H and mu c-SiOx:H as Both Doped and Intermediate Reflecting Layer for a-Si:H/a-Si1-xGex:H Tandem Solar Cells
(2016-07-01)
Chen, Po-Wei
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Chen, Pei-Ling
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Tsai, Chuang-Chuang
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光電工程學系
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Department of Photonics
In this work, we developed a-SiOx:H(n) and mu c-SiOx:H(n) films as n-type layer, intermediate reflecting layer (IRL), and back-reflecting layer (BRL) to improve the light management in silicon thin-film solar cells. In the development of SiOx:H films, by properly adjusting the oxygen content of the films, the optical bandgap of x-SiOx:H(n) can be increased while maintaining sufficient conductivity. Similar effect was found for a-SiOx:H(n). In a-Si:H single junction cells, employing a-SiOx:H(n) as the replacement for a-Si:H(n) resulted in a relative efficiency enhancement of 11.4% due to the reduced parasitic absorption loss. We have also found that pc-SiOx:H(n) can replace back ITO layer as BRL, leading to a relative efficiency gain of 7.6%. For a-Si:H/a-Sil..,Ge.,:H tandem cell, employing pf-SiOx:H(n) as IRL increased the current density of top cell. In addition, employing a-SiOx:H(n) as a replacement of a-Si:H(n) in the top cell increased the current density of bottom cell due to the reduction of absorption loss. Combining all the improvements, the a-Si:H/a-Si1-xGex:H tandem cell with efficiency of 9.2%, V-oc = 1.58 V, J(SC) = 8.43 mA/cm(2), and FF = 68.4% was obtained.
Development of Wider Bandgap n-type a-SiOx:H and mu c-SiOx:H as Both Doped and Intermediate Reflecting Layer for a-Si:H/a-Si1-xGex:H Tandem Solar Cells
(2016-07)
Chen, Po-Wei
;
Chen, Pei-Ling
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Tsai, Chuang-Chuang
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光電工程學系
;
Department of Photonics
In this work, we developed a-SiOx:H(n) and mu c-SiOx:H(n) films as n-type layer, intermediate reflecting layer (IRL), and back-reflecting layer (BRL) to improve the light management in silicon thin-film solar cells. In the development of SiOx:H films, by properly adjusting the oxygen content of the films, the optical bandgap of x-SiOx:H(n) can be increased while maintaining sufficient conductivity. Similar effect was found for a-SiOx:H(n). In a-Si:H single junction cells, employing a-SiOx:H(n) as the replacement for a-Si:H(n) resulted in a relative efficiency enhancement of 11.4% due to the reduced parasitic absorption loss. We have also found that pc-SiOx:H(n) can replace back ITO layer as BRL, leading to a relative efficiency gain of 7.6%. For a-Si:H/a-Sil..,Ge.,:H tandem cell, employing pf-SiOx:H(n) as IRL increased the current density of top cell. In addition, employing a-SiOx:H(n) as a replacement of a-Si:H(n) in the top cell increased the current density of bottom cell due to the reduction of absorption loss. Combining all the improvements, the a-Si:H/a-Si1-xGex:H tandem cell with efficiency of 9.2%, V-oc = 1.58 V, J(SC) = 8.43 mA/cm(2), and FF = 68.4% was obtained.
Dual gate indium-gallium-zinc-oxide thin film transistor with an unisolated floating metal gate for threshold voltage modulation and mobility enhancement
(2011-04-11)
Zan, Hsiao-Wen
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Chen, Wei-Tsung
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Yeh, Chung-Cheng
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Hsueh, Hsiu-Wen
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Tsai, Chuang-Chuang
In this study, we propose a floating dual gate (FDG) indium-gallium-zinc-oxide (IGZO) thin film transistor (TFT) with a floating metal back gate that is directly contact with IGZO without a dielectric layer. The floating back gate effect is investigated by changing the work function (phi) of the back gate. The FDG IGZO TFT exhibits an improved field-effect mobility (mu), unchanged subthreshold swing (SS), high on/off current ratio, and a tunable threshold voltage ranged (V(th)) from -5.0 to + 7.9 V without an additional back gate power supply. (C) 2011 American Institute of Physics. [doi:10.1063/1.3578403]
Dual-Sided Slim LCD Display System with UV Excited Flat Backlight
(2009)
Huang, Hsin-Tao
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Tsai, Chuang-Chuang
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Huang, Yi-Pai
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Hsiao, Chun-Chung
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Chen, Sung-Po
Dual-sided LCD displays are ideally suited for the public information display (PID) application. The UV excited flat lighting (UFL) was successfully demonstrated to perform dual-sided illumination with the features of flat lighting, uniform luminance and high brightness on a 42 '' TFT-LCD display. Compared to conventional CCFL or LED lighting source, UFL is superior for the dual-sided display application with its slim backlight module profile and power saving.
Effect of TCO/mu c-Si:H Interface Modification on Hydrogenated Microcrystalline Silicon Thin-Film Solar Cells
(2013)
Liang, Shin-Wei
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Hsu, Cheng-Hang
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Tsai, Chuang-Chuang
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光電工程學系
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Department of Photonics
The effects of H-2 plasma exposure on optical, electrical, and structural properties of fluorine-doped tin oxide (FTO) and AZO/FTO substrates have been investigated. With increasing the time of H-2-plasma exposure, the hydrogen radical and ions penetrated through the FTO surface to form more suboxides such as SnO and metallic Sn, which was confirmed by the XPS analysis. The Sn reduction on the FTO surface can be effectively eliminated by capping the FTO with a very thin layer of sputtered aluminum-doped zinc oxide (AZO), as confirmed by the XPS analysis. By using the AZO/FTO as front TCO with the subsequent annealing, the p-i-n mu c-Si:H cell exhibited a significantly enhanced JSC from 15.97 to 19.40 mA/cm(2) and an increased conversion efficiency from 5.69% to 7.09%. This significant enhancement was ascribed to the effective elimination of the Sn reduction on the FTO surface by the thin AZO layer during the Si-based thin-film deposition with hydrogen-rich plasma exposure. Moreover, the subsequent annealing of the sputtered AZO could lead to less defects as well as a better interface of AZO/FTO.
Effective Mobility Enhancement by Using Nanometer Dot Doping in Amorphous IGZO Thin-Film Transistors
(2011-10-04)
Zan, Hsiao-Wen
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Tsai, Wu-Wei
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Chen, Chia-Hsin
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Tsai, Chuang-Chuang
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光電工程學系
Enhancement of Spectral Response in mu c-Si1-xGex:H Thin-Film Solar Cells with a-Si:H/mu c-Si:H P-Type Window Layers
(2015-01-01)
Huang, Yen-Tang
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Hsu, Cheng-Hang
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Tsai, Chuang-Chuang
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光電工程學系
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光電工程研究所
The hydrogenated amorphous silicon (a-Si:H)/hydrogenated microcrystalline silicon (mu c-Si:H) double p-type window layer has been developed and applied for improving microcrystalline silicon-germanium p-i-n single-junction thin-film solar cells deposited on textured SnO2:F-coated glass substrates. The substrates of SnO2:F, SnO2:F/mu c-Si:H(p), and SnO2:F/a-Si: H(p) were exposed to H-2 plasma to investigate the property change. Our results showed that capping a thin layer of a-Si: H(p) on SnO2:F can minimize the Sn reduction during the deposition process which had H-2-containing plasma. Optical measurement has also revealed that a-Si: H(p) capped SnO2:F glass had a higher optical transmittance. When the 20 nm mu c-Si: H(p) layer was replaced by a 3 nm a-Si: H(p)/17 nm mu c-Si:H(p) double window layer in the cell, the conversion efficiency (eta) and the short-circuit current density (J(SC)) were increased by 16.6% and 16.4%, respectively. Compared to the standard cell with the 20 nm mu c-Si:H(p) window layer, an improved conversion efficiency of 6.19% can be obtained for the cell having a-Si:H(p)/mu c-Si: H(p) window layer, with V-OC = 490 mV, J(SC) = 19.50 mA/cm(2), and FF = 64.83%.
High-Current-Drive Dual-Gate a-IGZO TFT With Nanometer Dotlike Doping
(2013-10-01)
Liao, Chun-Hung
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Li, Chang-Hung
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
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Tsai, Chuang-Chuang
In this letter, we use a dual-gate (DG) structure together with nanometer dotlike doping (NDD) in active channel to produce a-IGZO thin-film transistors with very high current drive. With DG operation, the output current increases from 0.14 mA of the conventional device to 0.76 mA of the NDD device. The enhanced lateral field and improved carrier accumulation in DG operation may explain the significantly enlarged drive current. Particularly, simulated electron distribution reveals that high carrier concentration is induced under NDD regions in DG operation. The device without NDD, however, does not exhibit improved drive current in DG operation.
Highly Effective Field-Effect Mobility Amorphous InGaZnO TFT Mediated by Directional Silver Nanowire Arrays
(2015-01-14)
Liu, Hung-Chuan
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Lai, Yi-Chun
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Lai, Chih-Chung
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Wu, Bing-Shu
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Zan, Hsiao-Wen
In this work, we demonstrate sputtered amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) with a record high effective field-effect mobility of 174 cm(2)/V s by incorporating silver nanowire (AgNW) arrays to channel electron transport. Compared to the reference counterpart without nanowires, the over 5-fold enhancement in the effective field-effect mobility exhibits clear dependence on the orientation as well as the surface coverage ratio of silver nanowires. Detailed material and device analyses reveal that during the room-temperature IGZO sputtering indium and oxygen diffuse into the nanowire matrix while the nanowire morphology and good contact between IGZO and nanowires are maintained. The unchanged morphology and good interfacial contact lead to high mobility and air-ambient-stable characteristics up to 3 months. Neither hysteresis nor degraded bias stress reliability is observed. The proposed AgNW-mediated a-IGZO TFTs are promising for development of large-scale, flexible, transparent electronics.
Improved light management in a-Si:H/a-Si1-xGex:H tandem cells by employing multi-functional n-type microcrystalline silicon oxide
(2014-05-01)
Hsu, Hung-Jung
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Liang, Shin-Wei
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Huang, Yen-Tang
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Hsu, Cheng-Hang
;
Tsai, Chuang-Chuang
In this work, the development of plasma-enhanced chemical vapor deposition (PECVD) mu c-SiOx:H(n) and its application to a-Si:H/a-Si1-xGex:H tandem cells as the intermediate reflecting layer (IRL) and back reflector (BR) is presented. The n-type microcrystalline silicon oxide [mu c-SiOx:H(n)] was used as multifunctional layers in silicon thin-film solar cells owing to its wide bandgap and low refractive index. In the development of mu c-SiOx:H(n), increasing RF power increased film oxygen content, which widened the bandgap while reducing dark conductivity. Applying the mu c-SiOx:H to a-Si:H/a-Si1-xGex:H tandem cells as IRL and BR significantly improved cell performance. The mu c-SiOx:H(n) IRL increases the current of the top cell, thus improving the light management in a-Si:H/a-Si1-xGex:H tandem cells. On the other hand, the mu c-SiOx:H(n) can be used as the BR replacing the n-type a-Si:H and ITO layers. The mu c-SiOx:H increased cell conversion efficiency by 12.9% as IRL, and by 9.7% as BR, achieving 10.03% efficiency. (C) 2014 The Japan Society of Applied Physics
Improvement of a-Si1-xGex:H single-junction thin-film solar cell performance by bandgap profiling techniques
(2012-09-01)
Hsu, Hung-Jung
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Hsu, Cheng-Hang
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Tsai, Chuang-Chuang
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資訊工程學系
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Department of Computer Science
In this work, the effect of hydrogen dilution on the Ge content of the film and the effect of bandgap grading in the a-S1-xGex:H absorber near the p/i and the i/n interfaces on cell performance were discussed. The a-Si1-xGex:H single-junction solar cells were improved by employing both p/i grading and i/n grading. The i/n grading increased the V-OC and the FF while it also reduced the J(SC) as compared to the cell without grading. Presumably the potential gradient established by the i/n grading facilitates the hole transport hereby improved by the FF. On the contrary, the potential barrier established by the p/i grading seemed to limit the cell performance and constrain the p/i grading width below 20 nm due to the drop in FF and J(SC). Combining the effects of bandgap grading on the V-OC, J(SC) and FF, the suitable thicknesses of the p/i and the i/n grading were 20 nm and 45 nm, respectively. Finally, the grading structures accompanied with further optimization in doped layers were integrated to achieve a cell efficiency of 8.59%. (C) 2012 Elsevier B.V. All rights reserved.