Browsing by Author "Hsu, Chia-Chen"

Now showing 1 - 4 of 4

Hole transit in P3HT:PCBM solar cells with embedded gold nanoparticles
(2014-02-01)
Cheng, Cheng-En
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Pei, Zingway
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Hsu, Chia-Chen
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Chang, Chen-Shiung
;
Chien, Forest Shih-Sen
The electrical properties of polymer solar cells (PSCs) with gold nanoparticles (AuNPs) embedded in the hole transport layers (Hits) were investigated. The PSCs with AuNP-embedded HTLs exhibited 8%, 9.5%, and 22% enhancement in short-circuit current density, open-circuit voltage, and power conversion efficiency, respectively. The low contact resistance at the active layer/Hit interface resulted in the high collection efficiency and low electron-hole recombination. The downshift of the Fermi energy in AuNP-embedded HTLs lowered the energy barrier and thinned the depletion layer at the active layer/HTL interface, accounting for the enhanced collection efficiency. (C) 2013 Elsevier B.V. All rights reserved.
Optical controlled graphene-based nonvolatile ternary-logic transistor with azobenzene copolymer
(2013-01-07)
Lin, Chi-Yuan
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Chang, Chen-Shiung
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Lin, Jian Hung
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Hsu, Chia-Chen
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Chien, Forest Shih-Sen
We demonstrated optical-controlled graphene-based nonvolatile transistors incorporated with azobenzene copolymer. The transistor was gated by the quasi remnant polarization of azobenzene copolymer, which was built by photo-assisted poling and erased by photo-depoling at room temperature. By taking the nature of polymer electret of azobenzene copolymer, the graphene-based device can perform ternary logic, and the resistance change ratio of the written status "+/- 1" to the erased status "0" was -/+ 60%. The device can retain its statuses against an electric field as high as 0.2 MV/cm because the azobenzene molecules were frozen in copolymer at room temperature. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773984]
Optimized Memory Access Support for Data Layout Conversion on Heterogeneous Multi-core Systems
(2014-01-01)
Hsu, Chia-Chen
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Lin, Cheng-Yen
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Chen, Shin Kai
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Liu, Chih-Wei
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Lee, Jenq-Kuen
Heterogeneous multi-core systems that contain multiple CPUs and GPUs are gaining momentum, as they are providing different computation power to meet the performance demand of modern applications. On such systems, developers try to fully utilize the computation power both for CPU and GPU by using the emerging programming models such as CUDA and OpenCL. To achieve the maximal performance, developers must carefully offload the appropriate workload to the compute devices according to the characteristics of target architecture. Under such scenario, seamlessly data motion between different processors become crucial. Additionally, re-organizing the data layout to fit the target architectures, such as array-of-structure (AOS) for CPU, structure-of-array (SOA) for GPU, and coordinate (COO) format to ELLPACK (ELL) for sparse computation, address such concern. In this paper, we propose a hardware memory manager, which efficiently optimizes the conversion of data layouts for heterogeneous multi-core systems on-the-fly. We address coalescing and sparse format conversion issue in our design. A novel ping-pong transpose architecture is devised to reorganize non-coalescing access pattern, and a histogram unit and sparse address generator are presented to process sparse storage format transformation. Our design reduces the overhead of data transfer and layout transformation among CPU and GPU. In our experiment, our design achieves 68.5 to 2.19 times speed up comparing to software-based library depending on data size.
Surface-enhanced Raman scattering of graphene with photo-assisted-synthesized gold nanoparticles
(2013-03-11)
Cheng, Cheng-En
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Lin, Chi-Yuan
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Chang, Hao-Yu
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Huang, Chen-Han
;
Lin, Hsing-Ying
This paper presents a convenient and reliable method to prepare gold nanoparticles (AuNPs) on graphene. Photo-assisted synthesis (PAS) was employed to grow AuNPs in AuCl4- electrolyte on graphene. The size of AuNPs could be as large as 130 nm. This optical method had a steady growth rate of AuNPs. The distribution of AuNPs was well controlled by focusing the laser for PAS. The minimum diameter of the distribution was approximately 1 mu m. Surface-enhanced Raman scattering of graphene due to AuNPs was observed. Electrical fields near AuNPs calculated by the finite-difference time-domain algorithm ensured that the Raman enhancement was attributed to the localized surface plasmons of AuNPs. (c) 2013 Optical Society of America