Browsing by Author "Kang, Chen-Fang"

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A Nanostructuring Method to Decouple Electrical and Thermal Transport through the Formation of Electrically Triggered Conductive Nanofilaments
(2018-07-12)
Retamal, Jose Ramon Duran
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Kang, Chen-Fang
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Lien, Der-Hsien
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Kuo, Wei-Cheng
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Juang, Zhen-Yu
Transforming thermal energy into electric energy and vice versa needs the decoupling of electrical transport from thermal transport. An innovative strategy is proposed by forming/disrupting electrically triggered conductive nanofilaments within semiconducting thin films to switch thermoelectric properties between two states without further material modification and manufacturing processes. It can also controllably adjust the degree of decoupling, providing a potential resolution and performance adjustability for heat/coldness control or power consumption reduction on demand.
Few-Layer MoS2 with High Broadband Photogain and Fast Optical Switching for Use in Harsh Environments
(2013-05-01)
Tsai, Dung-Sheng
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Liu, Keng-Ku
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Lien, Der-Hsien
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Tsai, Meng-Lin
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Kang, Chen-Fang
Few-layered MoS2 as Schottky metal-semiconductor-metal photodetectors (MSM PDs) for use In harsh environments makes its debut as two-dimensional (2D) optoelectronics with high broadband gain (up to 13.3), high detectivity (up to similar to 10(10) cm Hz(1/2)/W), fast photoresponse (rise time of similar to 70 mu s and fall time of similar to 110 mu s), and high thermal stability (at a working temperature of up to 200 degrees C). Ultrahigh responsivity (0.57 A/W) of few-layer MoS2 at 532 nm is due to the high optical absorption (similar to 10% despite being less than 2 nm in thickness) and a high photogain, which sets up a new record that was not achievable in 2D nanomaterials previously. This study opens avenues to develop 2D nanomaterial-based optoelectronics for harsh environments in imaging techniques and light-wave communications as well as in future memory storage and optoelectronic circuits.
In Situ TEM and Energy Dispersion Spectrometer Analysis of Chemical Composition Change in ZnO Nanowire Resistive Memories
(2013-04-16)
Huang, Yu-Ting
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Yu, Shih-Ying
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Hsin, Cheng-Lun
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Huang, Chun-Wei
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Kang, Chen-Fang
Resistive random-access memory (ReRAM) has been of wide interest for its potential to replace flash memory in the next-generation nonvolatile memory roadmap. In this study, we have fabricated the Au/ZnO-nanowire/Au nanomemory device by electron beam lithography and, subsequently, utilized in situ transmission electron microscopy (TEM) to observe the atomic structure evolution from the initial state to the low-resistance state (LRS) in the ZnO nanowire. The element mapping of LRS showing that the nanowire was zinc dominant indicating that the oxygen vacancies were introduced after resistance switching. The results provided direct evidence, suggesting that the resistance change resulted from oxygen migration.
Self-formed conductive nanofilaments in (Bi, Mn)O-x for ultralow-power memory devices
(2015-04-01)
Kang, Chen-Fang
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Kuo, Wei-Cheng
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Bao, Wenzhong
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Ho, Chih-Hsiang
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Huang, Chun-Wei
Resistive random access memory (RRAM) is one of the most promising candidates as a next generation nonvolatile memory (NVM), owing to its superior scalability, low power consumption and high speed. From the materials science point of view, to explore optimal RRAM materials is still essential for practical application. In this work, a new material (Ni, Mn)0 (BMO) is investigated and several key performance characteristics of Pt/ BMO/Pt structured device, including switching performance, retention and endurance, are examined in details. Furthermore, it has been confirmed by high-resolution transmission electron microscopy that the underlying switching mechanism is attributed to formation and disruption of metallic conducting nanofilaments (CNFs). More importantly, the power dissipation for each CNF is as low as 3.8/20 fJ for set/reset process, and a realization of cross-bar structure memory cell is demonstrated to prove the downscaling ability of proposed RRAM. These distinctive properties have important implications for understanding switching mechanisms and implementing ultralow power-dissipation RRAM based on BMO. (C) 2015 Elsevier Ltd. All rights reserved.