Browsing by Author "Chen, Szu-Ying"

Now showing 1 - 5 of 5

Large Scale Single-Crystal Cu(In,Ga)Se(2) Nanotip Arrays For High Efficiency Solar Cell
(2011-10-01)
Liu, Chin-Hung
;
Chen, Chia-Hsiang
;
Chen, Szu-Ying
;
Yen, Yu-Ting
;
Kuo, Wei-Chen
In this paper, we demonstrated direct formation of large area Cu(In,Ga)Se(2), nanotip arrays (GIGS NTRs) by using one step Ar(+) milling process without template. By controlling milling time and incident angles, the length of CIGS NTRs with adjustable tilting orientations can be precisely controlled. Formation criteria of these CIGS NTRs have been discussed in terms of surface curvature, multiple components, and crystal quality, resulting in a highly anisotropic milling effect. The CIGS NTRs have very low reflectance <0.1% at incident wavelengths between 300 to 1200 nm. Open circuit voltage and short circuit current of CIGS NTRs solar cell were measured to be similar to 390 mV and similar to 22.56 mA/cm(2), yielding the filling factor and the efficiency of 59 and 5.2%, respectively. In contrast to CIGS thin film solar cell with efficiency of 3.2%, the nanostructured CIGS NTRs can have efficiency enhancement of similar to 160% due to the higher light absorption ability because of the nanostructure. The merits of current approach include the latest way via template-free direct creating process of nanostructured CIGS NTRs with controllable dimensionality and large scale production without postselenization process.
Large Scale Single-Crystal Cu(In,Ga)Se-2 Nanotip Arrays For High Efficiency Solar Cell
(2011-10-01)
Liu, Chin-Hung
;
Chen, Chia-Hsiang
;
Chen, Szu-Ying
;
Yen, Yu-Ting
;
Kuo, Wei-Chen
In this paper, we demonstrated direct formation of large area Cu(In,Ga)Se-2, nanotip arrays (GIGS NTRs) by using one step Ar+ milling process without template. By controlling milling time and incident angles, the length of CIGS NTRs with adjustable tilting orientations can be precisely controlled. Formation criteria of these CIGS NTRs have been discussed in terms of surface curvature, multiple components, and crystal quality, resulting in a highly anisotropic milling effect. The CIGS NTRs have very low reflectance <0.1% at incident wavelengths between 300 to 1200 nm. Open circuit voltage and short circuit current of CIGS NTRs solar cell were measured to be similar to 390 mV and similar to 22.56 mA/cm(2), yielding the filling factor and the efficiency of 59 and 5.2%, respectively. In contrast to CIGS thin film solar cell with efficiency of 3.2%, the nanostructured CIGS NTRs can have efficiency enhancement of similar to 160% due to the higher light absorption ability because of the nanostructure. The merits of current approach include the latest way via template-free direct creating process of nanostructured CIGS NTRs with controllable dimensionality and large scale production without postselenization process.
Large scale two-dimensional nanobowl array high efficiency polymer solar cell
(2012)
Chen, Szu-Ying
;
Yen, Yu-Ting
;
Chen, Yi-Yang
;
Hsu, Chain-Shu
;
Chueh, Yu-Lun
A two-dimensional nanobowl array (2D-NBRs) with a unique honeycomb nanostructure was demonstrated with controllable morphologies synthesized by the Langmuir-Blodgett (LB) method. The periodicity of 2D-NBRs can be controlled by utilizing different diameters of polystyrene (PS) balls ranged from 500 nm, 870 mu m, 1 mu m to 2 mu m. The reflectance measurements revealed that the planar structure with a poly(3-hexylthiophene) (P3HT)/(6,6)-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunction layer as an active layer exhibits a reflectance of similar to 20 %, while a significant reduction of the reflectance <5-7 % can be achieved after formation of 2D-NBRs at a PS ball diameter of 500 nm, which perfectly matches simulation results. From experimental results, the highest efficiency of 5.4 % with a filling factor of 66 % was achieved for the device with 2D-NBRs at PS ball diameter of 870 nm. Compared to a planar device with an efficiency of 3.9 %, a maximum enhancement of similar to 40 % can be achieved owing to the enhancement of Jsc because of unique honeycomb geometry, which exhibits a broadband and omnidirectional light harvesting behavior. Furthermore, a flexible solar cell was demonstrated with an enhanced efficiency of 30 % for a planar structure of 1 % to 1.3 % for 2D-NBRs structure.
Sensor-Based Approximate Adder Design for Accelerating Error-Tolerant and Deep-Learning Applications
(2019-01-01)
Huang, Ning-Chi
;
Chen, Szu-Ying
;
Wu, Kai-Chiang
;
資訊工程學系
;
Department of Computer Science
Approximate computing is an emerging strategy which trades computational accuracy for computational cost in terms of performance, energy, and/or area. In this paper, we propose a novel sensor-based approximate adder for high-performance energy-efficient arithmetic computation, while considering the accuracy requirement of error-tolerant applications. This is the first work using in-situ sensors for approximate adder design, based on monitoring online transition activity on the carry chain and speculating on carry propagation/truncation. On top of a fully-optimized ripple-carry adder, the performance of our adder is enhanced by 2.17X. When applied in error-tolerant applications such as image processing and handwritten digit recognition, our approximate adder leads to very promising quality of results compared to the case when an accurate adder is used.
Taper PbZr0.2Ti0.8O3 Nanowire Arrays: From Controlled Growth by Pulsed Laser Deposition to Piezopotential Measurements
(2012-03-01)
Chen, Yu-Ze
;
Liu, Te-Hsiang
;
Chen, Cheng-Ying
;
Liu, Chin-Hung
;
Chen, Szu-Ying
Single crystalline PbZr0.2Ti0.8 (PIT) nanowires arrays (NWAs) with taper morphology were epitaxially grown on SrTiO3 (STO) substrate using pulse laser deposition. The taper morphology was attributed to the overcoating of PIT layer via a lateral growth of Pit clusters/adatoms during PIT NW growth.. The growth window for PZT film or nanowire was systematically studied at varied temperatures and pressures. The proposed growth mechanism of the taper PIT NWAs was investigated from a layer by layer growth via Frank-Van Der Merwe growth, followed by a formation of three-dimensional islands via Stranski-Krastanow growth, and then axial growth on the lowest energy (001) plane with growth direction of [001] via vapor-solid growth mechanism. However, under certain conditions such as at higher or lower pressure (>400 or <200 mTorr) or substrate temperatures (>850 degrees C and <725 degrees C), formation of the PIT NWs is suppressed while the epltaxial Pit thin film via the layer-by-layer growth remains. The controllable growth directions of the PZT NWAs on (001), (110), and (111) STO substrates were demonstrated. The piezopotential of the taper PIT NWAs using a conducting atomic force microscope with the average voltage output of similar to 18 mV was measured. The theoretical piezopotential of a PIT NW was calculated to compare with the measured outputs, providing a comprehensively experimental and theoretical understanding of the piezoelectricity for the PZT NW.