Browsing by Author "Huang, Yu-Ting"

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Applications of Copolymers Consisting of 2,6-di(9H-carbazol-9-yl)pyridine and 3,6-di(2-thienyl)carbazole Units as Electrodes in Electrochromic Devices
(2019-04-02)
Kuo, Chung-Wen
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Chang, Jui-Cheng
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Huang, Yu-Ting
;
Chang, Jeng-Kuei
;
Lee, Li-Ting
A series of carbazole-based polymers (PdCz, P(dCz2-co-dTC1), P(dCz2-co-dTC2), P(dCz1-co-dTC2), and PdTC) were deposited on indium tin oxide (ITO) conductive electrodes using electrochemical polymerization. The as-prepared P(dCz2-co-dTC2) displayed a high T (57.0%) and multichromic behaviors ranging from yellowish green, greenish gray, gray to purplish gray in different redox states. Five organic electrochromic devices (ECDs) were built using dCz- and dTC-containing homopolymers and copolymers as anodic materials, and poly(3,4-(2,2-dimethylpropylenedioxy)thiophene) (PProdot-Me-2) as the cathodic material. The P(dCz2-co-dTC2)/PProdot-Me-2 ECD presented remarkable electrochromic behaviors from the bleached to colored states. Moreover, P(dCz2-co-dTC2)/PProdot-Me-2 ECD displayed a high optical contrast (T, 45.8%), short switching time (ca. 0.3 s), high coloration efficiency (528.8 cm(2) C-1) at 580 nm, and high redox cycling stability.
Copper silicide/silicon nanowire heterostructures: in situ TEM observation of growth behaviors and electron transport properties
(2013)
Chiu, Chung-Hua
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Huang, Chun-Wei
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Chen, Jui-Yuan
;
Huang, Yu-Ting
;
Hu, Jung-Chih
Copper silicide has been studied in the applications of electronic devices and catalysts. In this study, Cu3Si/Si nanowire heterostructures were fabricated through solid state reaction in an in situ transmission electron microscope (TEM). The dynamic diffusion of the copper atoms in the growth process and the formation mechanism are characterized. We found that two dimensional stacking faults (SF) may retard the growth of Cu3Si. Due to the evidence of the block of edge-nucleation (heterogeneous) by the surface oxide, center-nucleation (homogeneous) is suggested to dominate the silicidation. Furthermore, the electrical transport properties of various silicon channel length with Cu3Si/Si heterostructure interfaces and metallic Cu3Si NWs have been investigated. The observations not only provided an alternative pathway to explore the formation mechanisms and interface properties of Cu3Si/Si, but also suggested the potential application of Cu3Si at nanoscale for future processing in nanotechnology.
Direct observation of melting behaviors at the nanoscale under electron beam and heat to form hollow nanostructures
(2012)
Huang, Chun-Wei
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Hsin, Cheng-Lun
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Wang, Chun-Wen
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Chu, Fu-Hsuan
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Kao, Chen-Yen
"We report the melting behaviours of ZnO nanowire by heating ZnO-Al2O3 core-shell heterostructures to form Al2O3 nanotubes in an in situ ultrahigh vacuum transmission electron microscope (UHV-TEM). When the ZnO-Al2O3 core-shell nanowire heterostructures were annealed at 600 degrees C under electron irradiation, the amorphous Al2O3 shell became single crystalline and then the ZnO core melted. The average vanishing rate of the ZnO core was measured to be 4.2 nm s(-1). The thickness of the Al2O3 nanotubes can be precisely controlled by the deposition process. Additionally, the inner geometry of nanotubes can be defined by the initial ZnO core. The result shows a promising method to obtain the biocompatible Al2O3 nanotubes, which may be applied in drug delivery, biochemistry and resistive switching random access memory (ReRAM)."
Dynamic Evolution of Conducting Nanofilament in Resistive Switching Memories
(2013-08-01)
Chen, Jui-Yuan
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Hsin, Cheng-Lun
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Huang, Chun-Wei
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Chiu, Chung-Hua
;
Huang, Yu-Ting
Resistive random access memory (ReRAM) has been considered the most promising next-generation nonvolatile memory. In recent years, the switching behavior has been widely reported, and understanding the switching mechanism can improve the stability and scalability of devices. We designed an innovative sample structure for in situ transmission electron microscopy (TEM) to observe the formation of conductive filaments in the Pt/ZnO/Pt structure in real time. The corresponding current-voltage measurements help us to understand the switching mechanism of ZnO film. In addition, high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) have been used to identify the atomic structure and components of the filament/disrupted region, determining that the conducting paths are caused by the conglomeration of zinc atoms. The behavior of resistive switching is due to the migration of oxygen ions, leading to transformation between Zn-dominated ZnO1-x and ZnO.
ESD Improvements on Power N-Channel LDMOS Devices by the Composite Structure of Super Junctions Integrated With SCRs in the Drain Side
(2020-01-01)
Chen, Hung-Wei
;
Chen, Shen-Li
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Huang, Yu-Ting
;
Chen, Hsun-Hsiang
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電子工程學系及電子研究所
This paper studies a composite power n-channel lateral-diffused MOSFET device with a super junction (SJ) and parasitic silicon-controlled rectifier structure (nLDMOS-SJ-SCR) in the drain side, which can be used for electrostatic discharge (ESD) and latch-up (LU) reliability enhancements of 60-V power electronics. For ESD and LU protection considerations, the drain side with an SJ structure integrated with p-n-p- and n-p-n-arranged types of nLDMOS-SCR transistors is demonstrated. According to the experimental data, the layout of the SJ structure in the drain side has positive effects on ESD and LU capabilities. The layout type of nLDMOS-SJ with a pillar width W = 9 mu m has the highest secondary breakdown current (I-t2) values; the ESD (LU) improvement was 46.3% (13.3%) compared with the nLDMOS reference sample. Meanwhile, an nLDMOS-SJ with a pillar width W = 27 mu m has the highest figure of merit (FOM) value. By contrast, an embedded p-n-p-(n-p-n-)arranged type SCR structure was added into the drain side once again. Initially, it has a positive (negative) effect on the ESD reliability. Furthermore, the ESD (figure of merit; FOM) improvement was 37.9% (13.72%) of the corresponding nLDMOS-SJ device for nLDMOS-SJ-SCR (p-n-p) with W = 27 mu m. Overall, an nLDMOS-SJ device integrated with the p-n-p-arranged-type SCR in the drain side is a favorable choice for ESD and LU improvements.
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
;
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.
Mass transport phenomena in copper nanowires at high current density
(2016-04)
Huang, Yu-Ting
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Huang, Chun-Wei
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Chen, Jui-Yuan
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Ting, Yi-Hsin
;
Cheng, Shao-Liang
Electromigration in Cu has been extensively investigated as the root cause of typical breakdown failure in Cu interconnects. In this study, Cu nanowires connected to Au electrodes are fabricated and observed using in situ transmission electron microscopy to investigate the electro- and thermo-migration processes that are induced by direct current sweeps. We observe the dynamic evolution of different mass transport mechanisms. A current density on the order of 10(6) A/cm(2) and a temperature of approximately 400 A degrees C are sufficient to induce electro- and thermo-migration, respectively. Observations of the migration processes activated by increasing temperatures indicate that the migration direction of Cu atoms is dependent on the net force from the electric field and electron wind. This work is expected to support future design efforts to improve the robustness of Cu interconnects.
Measurement of Interlayer Screening Length of Layered Graphene by Plasmonic Nanostructure Resonances
(2013-10-31)
Chen, Hsiang-An
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Hsin, Cheng-Lun
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Huang, Yu-Ting
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Tang, Ming Lee
;
Dhuey, Scott
The variation in localized surface plasmon resonances of single Au nanodisks (diameter 100 nm and height 25 nm) on 0-13 graphene layers is investigated using dark-field scattering spectroscopy to obtain the graphene electric field screening length. For nanodisks (NDs) with and without underlying graphene layers on a SiO2 (300 nm)/Si substrate, the plasmon resonance red shifts from 604 to 620 nm with increasing graphene layers. The spectra of the plasmonic nanostructures obey an exponential saturation function versus increasing number of layers of graphene from 0 to 13. As a conducting film, the graphene layers screen the electric field generated by the plasmonic resonance of the Au NDs in the vicinity of the interface, and the red shifts of the resonance wavelength are explained in the framework of the electromagnetic field coupling between in-plane antiparallel image dipoles in the graphene layers and the ND dipole. A screening length of 1.2 +/- 0.2 nm, equivalent to 3-4 graphene layers, is experimentally obtained, in good agreement with the measurement by field-effect transistors and theoretical calculation in doped graphene. The resonance shift of plasmonic nanostructures on a layered graphene system provides an alternative and convenient method for screening length measurement of graphene films.
Nickel/Platinum Dual Silicide Axial Nanowire Heterostructures with Excellent Photosensor Applications
(2016-02)
Wu, Yen-Ting
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Huang, Chun-Wei
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Chiu, Chung-Hua
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Chang, Chia-Fu
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Chen, Jui-Yuan
Transition metal silicide nanowires (NWs) have attracted increasing attention as they possess advantages of both silicon NWs and transition metals. Over the past years, there have been reported with efforts on one silicide in a single silicon NW. However, the research on multicomponent silicides in a single silicon NW is still rare, leading to limited functionalities. In this work, we successfully fabricated beta-Pt2Si/Si/theta-Ni2Si, beta-Pt2Si/theta-Ni2Si, and Pt, Ni, and Si ternary phase axial NW heterostructures through solid state reactions at 650 degrees C. Using in situ transmission electron microscope (in situ TEM), the growth mechanism of silicide NW heterostructures and the diffusion behaviors of transition metals were systematically studied. Spherical aberration corrected scanning transmission electron microscope (Cs-corrected STEM) equipped with energy dispersive spectroscopy (EDS) was used to analyze the phase structure and composition of silicide NW heterostructures. Moreover, electrical and photon properties for the silicide nanowire heterostructures demonstrated promising applications in nano-optoeletronic devices. We found that Ni, Pt, and Si ternary phase nanowire heterostructures have an excellent infrared light sensing property which is absent in bulk Ni2Si or Pt2Si. The above results would benefit the further understanding of heterostructured nano materials. sensing
Real Time Observation of the Formation of Hollow Nanostructures through Solid State Reactions
(2014-05-06)
Lai, Huang-Yen
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Huang, Chun-Wei
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Chiu, Chung-Hua
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Wang, Chun-Wen
;
Chen, Jui-Yuan
We demonstrate the formation of hollow nickel germanide nanostructures of Ni-Ge core-shell nanoparticles by solid state reactions. The structural evolutions of nickel germanide hollow nanostructures have been investigated in real-time ultrahigh vacuum transmission electron microscopy (UHV-TEM). Annealed above 450 degrees C, the nonequilibrium interdiffusion of core and shell species occurred at the interface; thus, Ni germanide hollow nanostructures were formed by solid state reactions involving the Kirkendall effect. In addition, the different hollow nanostructures formed from different core diameters of Ni-Ge core-shell nanoparticles have been studied. Also, we propose the mechanism with effects of the size and annealing duration on the solid state reactions based on the Kirkendall effect.
Single-crystalline CuO nanowires for resistive random access memory applications
(2015-04-27)
Hong, Yi-Siang
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Chen, Jui-Yuan
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Huang, Chun-Wei
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Chiu, Chung-Hua
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Huang, Yu-Ting
Recently, the mechanism of resistive random access memory (RRAM) has been partly clarified and determined to be controlled by the forming and erasing of conducting filaments (CF). However, the size of the CF may restrict the application and development as devices are scaled down. In this work, we synthesized CuO nanowires (NW) (similar to 150 nm in diameter) to fabricate a CuO NW RRAM nanodevice that was much smaller than the filament (similar to 2 mu m) observed in a bulk CuO RRAM device in a previous study. HRTEM indicated that the Cu2O phase was generated after operation, which demonstrated that the filament could be minimize to as small as 3.8 nm when the device is scaled down. In addition, energy dispersive spectroscopy (EDS) and electron energy loss spectroscopy (EELS) show the resistive switching of the dielectric layer resulted from the aggregated oxygen vacancies, which also match with the I-V fitting results. Those results not only verify the switching mechanism of CuO RRAM but also show RRAM has the potential to shrink in size, which will be beneficial to the practical application of RRAM devices. (C) 2015 AIP Publishing LLC.
Single-crystalline delta-Ni2Si nanowires with excellent physical properties
(2013-06-19)
Chiu, Wen-Li
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Chiu, Chung-Hua
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Chen, Jui-Yuan
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Huang, Chun-Wei
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Huang, Yu-Ting
In this article, we report the synthesis of single-crystalline nickel silicide nanowires (NWs) via chemical vapor deposition method using NiCl2 center dot 6H(2)O as a single-source precursor. Various morphologies of delta-Ni2Si NWs were successfully acquired by controlling the growth conditions. The growth mechanism of the delta-Ni2Si NWs was thoroughly discussed and identified with microscopy studies. Field emission measurements show a low turn-on field (4.12 V/mu m), and magnetic property measurements show a classic ferromagnetic characteristic, which demonstrates promising potential applications for field emitters, magnetic storage, and biological cell separation.
Switching Kinetic of VCM-Based Memristor: Evolution and Positioning of Nanofilament
(2015-09-09)
Chen, Jui-Yuan
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Huang, Chun-Wei
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Chiu, Chung-Hua
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Huang, Yu-Ting
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Wu, Wen-Wei
The filament in a Au/Ta2O5/Au system is analyzed and determined to be a nanoscaled TaO2-x filament. A shrunken anode localizes the filament formation and the defect boundary leads to faster accumulation of oxygen vacancies. The defect changes the switching domination between electron transport and oxygen-vacancy migration. The migration of oxygen vacancies limits the filament dynamics, indicating the crucial role played by oxygen defects.