Browsing by Author "Yu, Pei-Chen"

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NANOSTRUCTURED THIN-FILM FORMED BY UTILIZING OBLIQUE-ANGLE DEPOSITION AND METHOD OF THE SAME
(2010-10-14)
Chang, Chia-Hua
;
Yang, Chin-Sheng
;
Chiu, Ching-Hua
;
Yu, Pei-Chen
;
Kuo, Hao-Chung
The present invention discloses a transparent conductive nanostructured thin-film by oblique-angle deposition and method of the same. An electron beam system is utilized to evaporate the target source. Evaporation substrate is disposed on a plurality of adjustable sample stage. Multiple gas control valve and heat source is provided to control the gas flow and temperature within the process chamber. An annealing process is performed after the evaporation to improve the thin-film structure and optoelectronic properties.
Nanostructured thin-film formed by utilizing oblique-angle deposition and method of the same
(2010-02-18)
Chang, Chia-Hua
;
Yang, Chin-Sheng
;
Chiu, Ching-Hua
;
Yu, Pei-Chen
;
Kuo, Hao-Chung
The present invention discloses a transparent conductive nanostructured thin-film by oblique-angle deposition and method of the same. An electron beam system is utilized to evaporate the target source. Evaporation substrate is disposed on a plurality of adjustable sample stage. Multiple gas control valve and heat source is provided to control the gas flow and temperature within the process chamber. An annealing process is performed after the evaporation to improve the thin-film structure and optoelectronic properties.
Optical-power-dependent photodesorption kinetics of graphene studied by conductance response
(2015-06-01)
Hsu, Yang-Yang
;
Lin, Chi-Yuan
;
Lai, Yi-Chun
;
Wu, Kun-Rui
;
Ng, Kwai-Kong
The photodesorption kinetics of graphene with various UV laser power is studied by conductance response. Analytical expressions of the power-dependent photodesorption kinetics of graphene in ambience are derived. The photodesorption time constant tau(d), steady current, and magnitude of modulation current, can be expressed as functions of the adsorption time constant tau(a), desorption cross section sigma, and photon flux density. Under illumination the steady occupation ratio of adsorbed O-2 on graphene is equal to tau(d)/tau(a). It is suggested that the photodesorption of O-2 on graphene is attributed the injection of photogenerated hot electrons and is restricted by the density of antibonding states of O-2. (C) 2015 Optical Society of America
Realization of Metal-Insulator Transition and Oxidation in Silver Nanowire Percolating Networks by Terahertz Reflection Spectroscopy
(2014-01-08)
Tsai, Yao-Jiun
;
Chang, Chi-Ying
;
Lai, Yi-Chun
;
Yu, Pei-Chen
;
Ahn, Hyeyoung
Metal nanowires (NWs) enable versatile applications in printed electronics and optoelectronics by serving as thin and flexible transparent electrodes. The performance of metal NWs as thin electrodes is highly correlated to the connectivity of NW meshes. The percolation threshold of metal NW films corresponds to the minimum density of NWs to form the transparent, yet conductive metal NW networks. Here, we determine the percolation threshold of silver NW (AgNW) networks by using morphological analysis and terahertz (THz) reflection spectroscopy. From the divergent behavior of carrier scattering time and the increase of carrier backscattering factor, the critical NW density at which crossover from Drude to non-Drude behavior of THz conductivity occurs can be unambiguously determined for AgNW thin films. Furthermore, the natural oxidation of AgNWs which causes the gradual reduction of the connectivity of the AgNW network is also realized by the THz spectroscopy. The selective oxidation of NW-to-NW junctions weakens the ohmic contact, and for AgNWs near a critical density, it can even lead to metal insulator transition. The presented results offer invaluable information to accelerate the deployment of metal nanowires for next-generation electronics and optoelectronics on flexible substrates.
Simulation of Grading Double Hetero-junction non-polar InGaN Solar cell
(2012)
Wang, Hsun-Wen
;
Yu, Pei-Chen
;
Han, Hau-Vei
;
Lin, Chien-Chung
;
Kuo, Hao-Chung
The characteristics of non-polar double heterojunction GaN/InxGa1-xN solar cells with various indium contents are numerically investigated. By smoothing the interface band edge offset with graded junction, the maximum efficiency reached 24.32 % as In0.6Ga0.4N. (C) 2012 Optical Society of America
Simulation of Grading Double Hetero-junction non-polar InGaN Solar cell
(2013)
Wang, Hsun-Wen
;
Yu, Pei-Chen
;
Han, Hau-Vei
;
Lin, Chien-Chung
;
Kuo, Hao-Chung
In this study, the characteristics of non-polar double heterojunction GaN/ InxGa1-xN solar cells with various indium contents are numerically investigated under AM 1.5 global spectrum using finite element analysis. By smoothing the interface band edge offset with graded junction, we see the enhancement on short circuit current and power conversion efficiency. The maximum efficiency of the simulation results reached 24,32 % when the major absorption region contains 65% of indium composition..
The influence of UV filter and Al/Ag moisture barrier layer on the outdoor stability of polymer solar cells
(2020-03-15)
Weng, Chia-Ning
;
Yang, Hao-Chun
;
Tsai, Cheng-Yu
;
Chen, Szu-Han
;
Chen, Yan-Syun
The degradation of the polymer solar cells in the outdoor condition was studied. It was found that the devices with normal structure (ITO/PEDOT:PSS/PBDTTT-EFT:PC71BM/ZrOx/Al) show better stability than those with inverted device structure (ITO/ZnO/PBDTTT-EFT:PC71BM/MoO3/Ag). PBDTTT-EFT is poly[4, 8-bis(5-(2-ethylhexyl) thiophen-2-yl) benzo [1,2-b;4,5-b] dithiophene-2, 6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno [3,4-b] thiophene-) - 2-carboxylate-2-6-diyl)] and PC71BM is [6,6]-phenyl-C71-butyric acid methyl ester. The major cause of degradation was attributed to the ultraviolet (UV) part of the sunlight. When the UV filter with cut-off wavelength of 400 nm was used to protect the device, the decay rate was improved by 50 times and the protected device retains 95% of their initial power conversion efficiency after 13 days outside. In the meanwhile, the decay of device fabricated by toluene was found 8 times faster than device by chlorobenzene. Thin 20 nm of Ag capping layer can further improve the stability. Degradation under water immersion indicates that the major effect of Ag is to protect against the residual moisture inside the encapsulation.
Three-dimensional indium-tin-oxide electrode, method of fabricating the same, device of fabricating the same, and method of fabricating solar cell comprising the same
(2010-12-09)
Chang, Chia-Hua
;
Yu, Pei-Chen
;
Hsu, Min-Hsiang
;
Wei, Kung-Hwa
;
Su, Ming-Shin
A three-dimensional ITO electrode and the method of fabricating the same are disclosed. The three-dimensional ITO electrode of the present invention has a conductive layer and a plurality of ITO nanorods formed on the conductive layer, wherein the length range of the ITO nanorods can vary from 10 nm to 1500 nm. The best length is about 50 nm-200 nm for organic solar cells. When applied into organic optoelectronic devices such as organic solar cells and organic light-emitting diodes (OLEDs), the three-dimensional structure of the ITO electrode may increase the contact area to the active layer, thus improving the electric current collecting efficiency and uniformity of current spreading (flowing). Also, an evaporator, a solar cell comprising the above three-dimensional ITO electrode, and the method of fabricating the solar cell are disclosed.
Transparent planar indium tin oxide for a thermo-photovoltaic selective emitter
(2020-09-01)
Chen, Yu-Bin
;
Parashar, Parag
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Yang, Yi-Hua
;
Rawat, Tejender Singh
;
Chen, Shih-Wei
Designing an efficient emitter design is an important step for achieving a highly efficient TPV conversion process. Wavelength-selective emissivity, spectra match between the emitter and TPV cells, and high thermal stability are three main characteristics that must be considered before implementing the emitter. In this work, an indium tin oxide (ITO)/sapphire emitter structure is investigated for TPV application over the temperature range from 200 degrees C to 1000 degrees C. A 1-mu m-thick ITO layer is deposited on a 650-mu m-thick sapphire substrate. In addition, 50-nm-thick SiO2 is deposited on top of the ITO to enhance the performance of emitter at high temperatures. High-temperature emissivity and absorptivity measurement of the emitter samples are obtained using FTIR and a Hitachi U-4100 spectrophotometer, respectively. The resultant SiO2/ITO/sapphire/stainless-steel planar emitter structure has selective emission with high emissivity of similar to 0.8 in the 1-1.6 mu m wavelength regime at 1000 degrees C. This emission range lies at the bandgap edge of silicon TPV cells and thus can be used to harness the true potential for making a low-cost thermophotovoltaic system. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement