Browsing by Author "Bow, Jong-Shing"

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A Fluorographene-Based Synaptic Transistor
(2019-08-13)
Liu, Bo
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Hong, Ming-Chun
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Sahoo, Mamina
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Ong, Bin Leong
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Tok, Eng Soon
Exploring brain-inspired synaptic devices has recently become a new focus of research in nanoelectronic communities. In this emerging field, incorporating 2D materials into three-terminal synaptic transistors has brought various advantages. However, achieving a stable and long-term weight-modulation in these synaptic transistors, which are typically based on interface charge storage, is still a challenge due to the nature of their spontaneous relaxation. The application of an atomically thin fluorographene layer into the synaptic junction region suppresses this issue and improves the efficiency, tunability, and symmetry of the synaptic plasticity as well as establishing a stable weight-regulation paradigm. These unique properties can be attributed to the dipolar rotation of C-F in fluorographene. To obtain a better physical understanding, a vacancy-dependent C-F dipolar rotation model is proposed and supported by hysteresis analysis and density functional theory calculations. As proposed and demonstrated, the unique fluorographene-based synaptic transistor may be a promising building block for constructing efficient neuromorphic computing hardware.
An electronic silicon-based memristor with a high switching uniformity
(2019-02-01)
Lu, Yang
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Alvarez, Ana
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Kao, Chung-Ho
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Bow, Jong-Shing
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Chen, San-Yuan
Metal-insulator-metal devices known as memristors offer voltage-regulated nanoscale conductivity and are of interest in the development of non-volatile random access memory. Typically, however, their tunable conductivity is the result of migrating ions within a stochastically formed filament, and as such their combined resistor-memory performance suffers. Here we show that amorphous silicon compositions, which are doped with oxygen or nitrogen and sandwiched between metal electrodes, can be used to create purely electronic memristors. The devices have coherent electron wave functions that extend to the full device thickness (more than 15 nm) and, despite the thinness and very high aspect ratio of the devices, electrons still follow an isotropic, three-dimensional pathway, thus providing uniform conductivity at the nanoscale. Such pathways in amorphous insulators are derived from overlapping gap states and regulated by trapped charge, which is stabilized by electron-lattice interaction. As a result, the nanometallic memristors also exhibit pressure-triggered insulator-to-metal transitions. Our silicon-based memristors, which could be readily integrated into silicon technology, are purely electronic and offer switching capabilities that are fast, uniform, durable, multi-state and low power.
Design and optimization of a nanoprobe comprising amphiphilic chitosan colloids and Au-nanorods: Sensitive detection of human serum albumin in simulated urine
(2016-12-30)
Jean, Ren-Der
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Larsson, Mikael
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Cheng, Wei-Da
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Hsu, Yu-Yuan
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Bow, Jong-Shing
Metallic nanoparticles have been utilized as analytical tools to detect a wide range of organic analytes. In most reports, gold (Au)-based nanosensors have been modified with ligands to introduce selectivity towards a specific target molecule. However, in a recent study a new concept was presented where bare Au-nanorods on self-assembled carboxymethyl-hexanoyl chitosan (CHC) nanocarriers achieved sensitive and selective detection of human serum albumin (HSA) after manipulation of the solution pH. Here this concept was further advanced through optimization of the ratio between Au-nanorods and CHC nanocarriers to create a nanotechnology-based sensor (termed CHC-AuNR nanoprobe) with an outstanding lower detection limit (LDL) for HSA. The CHC-AuNR nanoprobe was evaluated in simulated urine solution and a LDL as low as 1.5 pM was achieved at an estimated AUNR/CHC ratio of 2. Elemental mapping and protein adsorption kinetics over three orders of magnitude in HSA concentration confirmed accumulation of HSA on the nanorods and revealed the adsorption to be completed within 15 min for all investigated concentrations. The results suggest that the CHC-AuNR nanoprobe has potential to be utilized for cost-effective detection of analytes in complex liquids. (C) 2016 Elsevier B.V. All rights reserved.
Development and photoluminescence of ZnO-ZnS core-shell nanotube and nanorod arrays
(2007)
Kuo, Pai-Chia
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Chen, San-Yuan
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Bow, Jong-Shing
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材料科學與工程學系
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Department of Materials Science and Engineering
After the wurtzite ZbS nanorods were synthesized by hydrothermal treatment in the presence of ethylenediamine (en) aqueous solutions at 200oC, ZnS-ZnO core-shell nanorods were readily obtained by annealing ZnS nanorods under oxygen at 650oC for 3-5 min. A strong broad peak in the 450-550 nm visible range was clearly detected and its peak intensity could be greatly enhanced after the ZnO shell was developed on hydrothermal ZnS nanorods. On the other hand, using AAO as a template, ZnS-ZnO core-shell nanotubes could be synthesized using atomic layer deposition process along with the sulfuration conversion of the ZnO nanotube array. This ZnO-ZnS core-shell nanotube structure could be confirmed by x-ray photoelectron spectroscopy (XPS) analysis. In addition, an enhanced UV emission along with the reduced visible emission was also detected for the ZnO/ZnS core-shell nanotubes.
Highly electrostatically-induced detection selectivity and sensitivity for a colloidal biosensor made of chitosan nanoparticle decorated with a few bare-surfaced gold nanorods
(2014-02-15)
Jean, Ren-Der
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Cheng, Wei-Da
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Hsiao, Meng-Hsuan
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Chou, Fu-Hsuan
;
Bow, Jong-Shing
Metallic nanoparticles have been utilized as an analytical tool to detecting a wide variety of organic analytes. Among them, gold nanoparticles demonstrating outstanding surface plasmonic resonance property have been well recognized and received wide attention for plasmon-based sensing applications. However, in literature, gold-based nanosensor has to be integrated with specific "ligand" molecule in order to gain molecular recognition ability. However, "ligand" molecules, included proteins, peptides, nucleic acids, etc. are expensive and vulnerable to environmental change, in the meantime, anchoring procedure of the "ligand" molecules to gold surface may be cost-ineffective and endangered to the ligand's activity, making a final analytic probe less reliable and risk in production capability. Here, we develop a new approach by designing a colloid-type sensor using a few "bare" Au nanorods deposited on the surface of a colloidal chitosan carrier. By tuning the solution pH, the resulting colloidal nanoprobe is capable of detecting proteins, i.e., human serum albumin and lysozyme, with high specificity and sensitivity. This new approach allows a new type of the molecular probes to be well manipulated to monitor important biomolecules for medical detection, diagnosis, and bioengineering applications. (C) 2013 Elsevier B.V. All rights reserved.