Browsing by Author "Dai, Bau-Tong"

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CIGS solar cell integrated with high mobility microcrystalline Si TFTs on 30X40 cm(2) glass panels for self powered electronics
(2012-01-01)
Shen, Chang-Hong
;
Shieh, Jia-Min
;
Wu, Tsung-Ta
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Huang, Jung Y.
;
Huang, Che-Hsuan
For the first time, we report a novel self-powered TFT panel (30X40cm(2)) by integration of sputtering/non-toxic Se vapor selenization copper-indium-gallium-selenide (CIGS) solar cell (conversion efficiency of 8%) and high electron-mobility (172 cm(2)/V-s) micro-crystalline (mu c)-Si TFTs.
Fast programming metal-gate Si quantum dot nonvolatile memory using green nanosecond laser spike annealing
(2012-04-02)
Lien, Yu-Chung
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Shieh, Jia-Min
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Huang, Wen-Hsien
;
Tu, Cheng-Hui
;
Wang, Chieh
The ultrafast metal-gate silicon quantum-dot (Si-QD) nonvolatile memory (NVM) with program/erase speed of 1 mu s under low operating voltages of +/-7V is achieved by thin tunneling oxide, in situ Si-QD-embedded dielectrics, and metal gate. Selective source/drain activation by green nanosecond laser spike annealing, due to metal-gate as light-blocking layer, responds to low thermal damage on gate structures and, therefore, suppresses re-crystallization/deformation/diffusion of embedded Si-QDs. Accordingly, it greatly sustains efficient charge trapping/de-trapping in numerous deep charge-trapping sites in discrete Si-QDs. Such a gate nanostructure also ensures excellent endurance and retention in the microsecond-operation Si-QD NVM. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3700729]
Growth enhancement and field emission characteristics of one-dimensional 3,4,9,10-perylenetetracarboxylic dianhydride nanostructures on pillared titanium substrate
(2007-10-01)
Suen, Shich-Chang
;
Whang, Wha-Tzong
;
Hou, Fu-Ju
;
Dai, Bau-Tong
;
材料科學與工程學系
We have utilized the pi-pi interactions between 3,4,9, 1 0-perylenetetracarboxylic dianhydride (PTCDA) molecules and temperature-induced morphology changes to synthesize one-dimensional (ID) nanostructures of PTCDA on a heated (ca. 100 degrees C) titanium substrate through vacuum sublimation. Because of the pillared Ti structures and the presence of reactive Ti-Cl sites, the titanium substrate played a crucial role in assisting the PTCDA molecules to form ID nanostructures. The average diameter of the nanofibers deposited on the Ti-CVD substrate, a Ti substrate formed by chemical vapor deposition (CVD), at 100 degrees C was ca. 84 run, with lengths ranging from 100 nm to 3 mu m. When the PTCDA nanofibers were biased under vacuum, the emission current remained stable. The turn-on electric field for producing a current density of 10 mu A/cm(2) was 8 V/mu m. The maximum emission current density was 1.3 mA/cm(2), measured at 1100 V (E = 11 V/mu m). From the slope of the straight line obtained after plotting ln(J/E-2) versus 1/E, we calculated the field enhancement factor beta to be ca. 989. These results demonstrate the PTCDA nanofibers have great potential for applicability in organic electron-emitting devices. (C) 2007 Elsevier B.V. All rights reserved.
Inductively coupled plasma grown semiconductor films for low cost solar cells with improved light-soaking stability
(2011-07-18)
Shen, Chang-Hong
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Shieh, Jia-Min
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Huang, Jung Y.
;
Kuo, Hao-Chung
;
Hsu, Chih-Wei
We investigate the performance of a single-junction amorphous Si (a-Si) solar cell fabricated with inductively coupled plasma (ICP) deposition technique. The high-density plasma resulting from high dissociation capacity of ICP enables good-quality hydrogenated Si films to be synthesized at low temperatures. High-density ICP also promotes the diffusion of reactive radicals on substrates and forms a-Si:H films with low defect density (similar to 3 x 10(15) cm(-3)). We demonstrate single-junction a-Si solar cells with a conversion efficiency of 9.6% and improved light-soaking stability. This low thermal-budget thin-film technique could open up the feasibility of efficient thin film solar cells on flexible substrates. (C) 2011 American Institute of Physics. [doi:10.1063/1.3615650]
Low cost high-efficiency amorphous silicon solar cells with improved light-soaking stability
(2012-03-01)
Huang, Jung Y.
;
Lin, Chien Y.
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Shen, Chang-Hong
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Shieh, Jia-Min
;
Dai, Bau-Tong
We investigate the performance of amorphous Si (a-Si) solar cells fabricated with Inductively Coupled Plasma (ICP) deposition technique. The ICP system produces a-Si films with low defect density (3 x 10(15) cm(-3)), resulting in a conversion efficiency of 9.6%. Deep level transient spectroscopy (DLTS) reveals that hole carriers trapped at defects near the valence band edge delocalize at 130 K: while trapped electrons can only be emitted into the conduction band near room temperature. Spectrally resolved DLTS study further indicates that light soaking enhances the emission rate of the tapped electrons near the conduction band edge while reduces the transition moments from the hole-trapping defect levels to the conduction band. The combined effects and light soaking-induced defects are responsible for the degradation of a thin film solar cell by light soaking. (C) 2011 Elsevier B.V. All rights reserved.
Low-temperature self-assembly of copper phthalocyanine nanofibers
(2006-10-01)
Suen, Shich-Chang
;
Whang, Wha-Tzong
;
Hou, Fu-Ju
;
Dai, Bau-Tong
;
材料科學與工程學系
This paper describes a method for producing ID organic nanofibers by exploiting intermolecular dispersive forces during the self-assembly of CuPc molecules. The average length of these CuPc nanofibers deposited at 100 degrees C, a temperature much lower than that required for the synthesis of carbon nanotubes, was ca. 500 nm, with diameters in the range 1550 nm. XRD analysis of these nanofibers revealed that they possessed an alpha phase structure. HRTEM images indicated that the CuPc nanofibers formed through layered stacking of CuPc molecules. These CuPc nanofibers exhibit field emission characteristics (with a turn-on field of 13.6 V/mu m) and follow Fowler-Nordheim behavior in a manner similar to that of carbon nanotubes. The stable emission current and relative simplicity of their synthesis suggest a broad range of applications for CuPc nanofibers in nanoscience and nanotechnology. (C) 2006 Elsevier B.V. All rights reserved.
Near Infrared Silicon Quantum Dots MOSFET Detector
(2009-01-01)
Shieh, Jia-Min
;
Yu, Wen-Chien
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Wang, Chao-Kei
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Dai, Bau-Tong
;
Kuo, Hao-Chung
Fully Si-based MOSFET photodetector was demonstrated at optical telecommunication wavelengths by using a gate dielectric stack comprising of a Si quantum dots film. Illumination at wavelengths lambda=1.55 mu m, photoresponse as high as 2.0A/W was measured. (C) 2009 Optical Society of America
Near-infrared silicon quantum dots metal-oxide-semiconductor field-effect transistor photodetector
(2009-06-15)
Shieh, Jia-Min
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Yu, Wen-Chien
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Huang, Jung Y.
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Wang, Chao-Kei
;
Dai, Bau-Tong
A fully silicon-based metal-oxide-semiconductor field-effect transistor is demonstrated for the detection of near-infrared light. Si nanocrystals (nc-Si) are synthesized in the nanopore channels of mesoporous silica (MS) inserted between two oxide layers to form a complete gate structure of polycrystalline Si/SiO(2)/nc-Si-in-MS/SiO(2) with a polycrystalline Si electrode. Illuminating the gate with near-infrared light, a photoresponsivity as high as 2.8 A/W at 1.55 mu m can be achieved. The improved photoresponsivity is attributed to from optical transitions via interface states and a current amplification mechanism of the device.
Near-omni-directional sub-micron Silica light-trapping monolayer for amorphous Si photovoltaic devices
(2011)
Huang, Wen-Hsien
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Shieh, Jia-Min
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Shen, Chang-Hong
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Huang, Jung Y.
;
Kuo, Hao-Chung
The non-closely packed (surface-coverage of 55-65%) sub-micron silica sphere (400 nm) light-trapping monolayer was introduced to boost photocurrent (efficiency) of thin film amorphous solar cells by 15% (6.9%). The enhancement is nearly omni-directional.
Nonvolatile memory with switching interfacial polar structures of nano Si-in-mesoporous silica
(2009-10-05)
Shieh, Jia-Min
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Huang, Jung Y.
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Yu, Wen-Chien
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Huang, Jian-Da
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Wang, Yi-Chao
We show an artificially engineered electret with Si nanocrystals embedded in mesoporous silica for nonvolatile memory. We attribute the polarization to from polar layers lying at the interfaces between one-side bonded Si nanocrystals and mesoporous silica matrix. Under external field, the Si nanocrystals could be displaced in the porechannels causing displaced charge distributions and therefore a field-controllable electric polarization. Nonvolatile memory is demonstrated with a metal-oxide-semiconductor field-effect transistor. (C) 2009 American Institute of Physics. [doi:10.1063/1.3240888]
Novel 140 degrees C Hybrid Thin Film Solar Cell/Transistor Technology with 9.6% Conversion Efficiency and 1.1 cm2/V-s Electron Mobility for Low-Temperature Substrates
(2010)
Shen, Chang-Hong
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Shieh, Jia-Min
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Kuo, Hao-Chung
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Huang, Jung Y.
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Huang, Wen-Hsien
For the first time, we report a low temperature silicon thin film deposition technology using high density plasma for high performance and low cost solar cells with embedded transistor modules. For process temperature at 140 degrees C, energy conversion efficiency of 9.6% and electron mobility of 1.1 cm(2)/V-s have been achieved. Device performance with process temperature down to 90 degrees C and 60 degrees C has also been examined in depth. This very low process temperature technology can integrate energy harvesting with electronics on inexpensive and flexible substrates.
Optical sum-frequency generation and Ferroelectric-like Switching in Si-O Polar Structures
(2009-01-01)
Shieh, Jia-Min
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Yu, Wen-Chien
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Huang, Jung Y.
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Wang, Yi-Chao
;
Chen, Ching-Wei
Optical sum-frequency generation and ferroelectric-like switching in Si-O polar structures comprised of Si nanocrystals (nc-Si) in mesoporous silica was reported and attributed to polar layers lying at the interfaces between one-side bonded nc-Si and host. (C) 2009 Optical Society of America
Stable and near-omni-directional high-efficiency amorphous Si photovoltaic devices
(2011)
Hsu, Chih-Wei
;
Shieh, Jia-Min
;
Shen, Chang-Hong
;
Huang, Jung Y.
;
Kuo, Hao-Chung
Highly stable high-density plasma-fabricated amorphous Si solar cells (7-9%) exhibit ultra-low photo-induced degradation in conversion-efficiency by 5.7%. This photovoltaic device with low-defect absorption layer is also a near-omni-directional solar-electricity generator.
Thin Film Silicon Solar Cell Fabricated at 100 degrees C by High Density Plasma for Flexible Photovoltaic Application
(2010-01-01)
Shen, Chang-Hong
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Shieh, Jia-Min
;
Kuo, Hao-Chung
;
Huang, Jung Y.
;
Yu, Wen-Chien
Record fabrication temperature, 100 degrees C, of a single junction amorphous Si solar cell was demonstrated by a high-density plasma method. Present solar cell revealed conversion efficiency of 7.4% at 200 degrees C (4.1% at 135 degrees C). (C) 2009 Optical Society of America
UV-Visible Light-Trapping Structure of Loosely Packed Submicrometer Silica Sphere for Amorphous Silicon Solar Cells
(2012-07-01)
Huang, Wen-Hsien
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Shieh, Jia-Min
;
Pan, Fu-Ming
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Shen, Chang-Hong
;
Lien, Yu-Chung
We synthesized a loosely packed submicrometer silica-sphere (LPSS) monolayer at room temperature and used the LPSS monolayer as the frontside light-trapping structure for n-i-p-type amorphous Si (a-Si) solar cells (SCs) to improve photovoltaic characteristics of the cells. The frontside LPSS monolayer plays a role as a UV-visible light scatter and a broadband antireflector; both can greatly improve the photoresponse of the underneath a-Si adsorbed layer. When the filling density of the LPSS layer is optimized to 65%, the enhancement in the photocurrent and conversion efficiency of the 120 degrees C-fabricated SCs is as high as similar to 15% and similar to 6.9%, respectively. Accordingly, such an LPSS light-trapping structure boosts efficiency of 120 degrees C- and 140 degrees C-fabricated cells to 7.3% and 8.5%, respectively. Since the LPSS structure has a graded refractive index profile, it behaves like a nearly omnidirectional antireflector, enhancing solar efficiency at a very large incident angle of illumination.