Browsing by Author "Chen, Hsuen-Li"

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Alignment of Stretchable Nanoparticle Chains with Tunable Optical Properties Formed from Molecular Machinery
(2013-01-01)
Lin, Ming-Yu
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Lu, Yen-Pei
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Yang, Yuh-Shyong
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Chen, Hsuen-Li
;
Yang, Chih-Hui
Control orientation and interparticle spacing of self-assembled nanoparticles can provide versatile functional materials for optical and electronic applications. In this study, we have obtained a glass substratum with tunable optical properties using flowing control and bimolecular competition. The surface of glass was modified from immobilized stretchable gold nanoparticle chains. The long and periodic single-stranded DNA nanotemplates were prepared using Phi29 DNA polymerase molecular machinery according to precise molecular biology regulation. Gold nanoparticle (Au NP) docked at the default sites of the nanotemplates and optical anisotropic absorption were enhanced by approximately 55 % by using tunable, flexible, and oriented one-dimensional metallic nanostructures.
Broadband and wide angle antireflection of sub-20 nm GaAs nanograss
(2012-06-01)
Ravipati, Srikanth
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Shieh, Jiann
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Ko, Fu-Hsiang
;
Yu, Chen-Chieh
;
Chen, Hsuen-Li
GaAs nanograss with diameters of less than 20 nm has been fabricated using a simple, one-step, maskless plasma etching-based approach. GaAs nanograss exhibits remarkable broadband antireflection properties, which arise from the graded refractive index between air and the GaAs substrate by the nanograss layer. Moreover, GaAs nanograss shows less sensitivity to transverse electric polarized light and transverse magnetic polarized light over a wide range of incident angles compared to the strong variation in a bare GaAs substrate. These effects show that sub-20 nm GaAs nanograss with lengths of approximately 200 nm has an enhanced absorption of 98-100% when the incident energy is larger than the GaAs bandgap (lambda = 240-873 nm) and an enhanced absorption of 72-98% when the incident energy is less than the bandgap (lambda = 873-2400 nm). Our simple, one-step, and maskless plasma etching method opens a promising approach for the direct implementation of broad omnidirectional antireflective surfaces on solar cells and various optoelectronic devices to improve device performance.
Creation of 3D Textured Graphene/Si Schottky Junction Photocathode for Enhanced Photo-Electrochemical Efficiency and Stability
(2019-08-01)
Ku, Che-Kuei
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Wu, Po-Hsieh
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Chung, Cheng-Chu
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Chen, Chun-Chi
;
Tsai, Kaijie
This work presents a novel photo-electrochemical architecture based on the 3D pyramid-like graphene/p-Si Schottky junctions. Overcoming the conventional transfer technique by which only planar graphene/Si Schottky junctions are currently available, this work demonstrates the 3D pyramid-like graphene/p-Si Schottky junction photocathode, which greatly enhances light harvesting efficiency and exhibits promising photo-electrochemical performance for hydrogen generation. The formation of 3D pyramid-like graphene/p-Si Schottky junctions exhibits enhanced electrochemical activity and promotes charge separation efficiency compared with the bare pyramid Si surface without graphene. The inherent chemical inertness of graphene significantly improves the operational stability of 3D graphene/p-Si Schottky junction photo-electrochemical cells. The 3D pyramid-like graphene/p-Si Schottky junction photocathode delivers an onset potential of 0.41 V and a saturated photocurrent density of -32.5 mA cm(-2) at 0 V (vs RHE) with excellent stability comparable to values reported for textured or nanostructured p-Si photocathodes coated with ultrathin oxide layers by the conventional atomic layer deposition technique. These results suggest that the formation of graphene/Si Schottky junctions with a 3D architecture is a promising approach to improve the performance and durability of Si-based photo-electrochemical systems for water splitting or solar-to-fuel conversion.
Efficiency Enhancement and Sensitive Broadband 1Hz similar to 1kHz of Power Generator by Recycling Vibration Energy on Automobile
(2012)
Wei, Mao-Qugn
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Ko, Fu-Hsiang
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Sun, Tai-Ping
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Chen, Hsuen-Li
;
Lin, Yung-Bin
Based on novel design of moveable magnet between two mutually inimical magnetic forces without strict fabrication, for the first time, we demonstrate successfully a producible power generator with significant efficiency enhancement at broadband frequency range of 1 Hz similar to 1 kHz, 3D-colis stack-ability for output voltage improvement, and recycling vibration energy on automobile simultaneously. Even though the vibration frequency is as low as 1 Hz, two orders-of-magnitude improvements in normalized power (the ratio of power to product of external force and coil turns) provided from previous reports can be obtained. Further, comparing our device with maturely accelerometer chip (MMA7361) indicates that proposed strategies benefit harvesting vibration energy on driving automobile indeed. This vibrated power generator in-turn provides high potential for applications, such as human motion (1 Hz similar to 2 Hz), sporting (5 Hz similar to 10 Hz), and automotive (10 Hz similar to 1 kHz) etc..
Influence of the mask magnification on imaging in hyper-NA lithography
(2007-06-01)
Lin, Chun-Hung
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Chen, Hsuen-Li
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Ko, Fu-Hsiang
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材料科學與工程學系奈米科技碩博班
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Graduate Program of Nanotechnology , Department of Materials Science and Engineering
Argon fluoride laser (ArF) lithography using immersion technology has the potential to extend the application of optical lithography to 45 nm half-pitch and possibly beyond. By keeping the same 4X magnification factor, the dimensions of the structures on masks are becoming comparable to the exposure wavelength or even smaller. The polarization effect induced by mask features is, however, an issue. The introduction of a larger mask magnification should be strongly considered when poor diffraction efficiencies from subwavelength mask features and the resulting image degradation would be encountered in hyper-NA lithography. The dependence of the diffraction efficiencies on mask pitch and illuminating angle are evaluated. The near-field intensity and phase distributions from the mask are calculated. The imaging performance of 4X and 8X masks for the sub-45 nm node are explored. A rigorous coupled-wave analysis is developed and employed to analyze the optical diffraction from the 3D topographic periodic features. (C) 2007 Optical Society of America
Rigorous electromagnetic simulation of mask magnification effects on the diffracted light for EUV binary mask
(2007-05-01)
Lin, Chun-Hung
;
Chen, Hsuen-Li
;
Ko, Fu-Hsiang
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材料科學與工程學系奈米科技碩博班
;
Graduate Program of Nanotechnology , Department of Materials Science and Engineering
Extreme ultraviolet (ELTV) lithography is expected to be the main candidate in the semiconductor manufacturing starting at 32 nm. As the CD is getting smaller, the aspect ratio of the patterns on the ELTV mask is becoming larger. The shadowing effect will become much more significant when keeping the same 4x mask magnification. In this work, mask magnification effects on the diffracted light were explored with rigorous coupled-wave analysis (RCWA) for the sub-32 nm node. The simulated binary mask consists of 70-nm TaBN absorber and 2.5-nm Ru capping layer. The dependences of the diffraction efficiencies on mask pitches were calculated. The impacts of the absorber shadowing were observed from the near field distribution on the EUV mask. The aerial images formed by the diffracted light from the 4x and 8x masks were further evaluated. (c) 2007 Elsevier B.V. All rights reserved.
Ultralow Reflection from a-Si Nanograss/Si Nanofrustum Double Layers
(2013-03-25)
Ravipati, Srikanth
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Shieh, Jiann
;
Ko, Fu-Hsiang
;
Yu, Chen-Chieh
;
Chen, Hsuen-Li
A double-layer nanostructure comprising amorphous Si nanograss on top of Si nanofrustums (NFs) with a total height of 680 nm exhibits ultralow reflection. Almost near-unity absorption and near-zero reflectance result in this layered nanostructure, over a broad range of wavelengths and a wide range of angles of incidence, due to the low packing density of a-Si and the smooth transition of the refractive index from the air to the Si substrate across both the nanograss and NF layers.