學術出版;;Publications

Permanent URI for this communityhdl:11536/1

收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

Browse

🏛️國立陽明交通大學機構典藏

Search Results

Now showing 1 - 10 of 189

Mechanical Modulation of Colossal Magnetoresistance in Flexible Epitaxial Perovskite Manganite
(1970-01-01)
Yen, Min
;
Lai, Yu-Hong
;
Kuo, Chang-Yang
;
Chen, Chien-Te
;
Chang, Chun-Fu
Heteroepitaxially flexible oxide systems have been intensely developed and considered as the most promising materials for leading the creation of next-generation flexible electronic devices. Among them, perovskite manganites have attracted significant attention with their abundant and novel properties such as colossal magnetoresistance (CMR) and metal-insulator transition. However, the requirement of high quality samples hampers this field, not to mention the advanced nanoengineering. In this study, fluorophlogopite mica (F-mica) is selected as a flexible substrate to fabricate heteroepitaxial Pr0.5Ca0.5MnO3(PCMO) with a nanocolumn structure. Through a precise control of thickness, different morphologies are realized to manipulate the magnetotransport properties (reduction of melting field). Moreover, thanks to the excellent flexibility of F-mica, mechanical modulation of CMR (approximate to 1000%) can be achieved in different flex modes while the magnetic properties remain unaffected. Detailed bending tests are performed to study the behavior of resistive change (approximate to 30%). Through the combination of high flexibility, high quality PCMO, and well-designed nanocolumn structure, the study exhibits the significant controllability of CMR via mechanical bending, and manifests the potential of such a heteroepitaxially flexible oxide system which can be applied on flexible magnetoresistive devices and sensors.
Giant Resistivity Change of Transparent ZnO/Muscovite Heteroepitaxy
(2020-05-13)
Yen, Min
;
Lai, Yu-Hong
;
Zhang, Chun-Li
;
Cheng, Hou-Yung
;
Hsieh, Yi-Ting
The piezoresistive effect has shown a remarkable potential for mechanical sensor applications and been sought for its excellent performance. A great attention was paid to the giant piezoresistive effect and sensitivity delivered by silicon-based nanostructures. However, low thermal stability and complicated fabrication process hinder their practical applications. To overcome these issues and enhance the functionalities, we envision the substantial piezopotential in a zinc oxide (ZnO)/muscovite (mica) heteroepitaxy system based on theoretical consideration and realize it in practice. High piezoresistive effect with giant change of resistivity (-80 to 240%) and large gauge factor (>1000) are demonstrated through mechanical bending. The detailed features of heteroepitaxy, electrical transport, and strain are probed to understand the mechanism of such a giant resistivity change. In addition, a bending model is established to reveal the distribution of strain. Finally, we demonstrate a flex sensor featuring high sensitivity, optical transparency, and two-segment sensing with a great potential toward practical applications. Such an oxide heteroepitaxy exhibits excellent piezoresistive properties and mechanical flexibility. In the near future, the importance of flex sensors will emerge because of the precise control in the automation industries, and our results lead to a new design in the field of flex sensors.
Transparent Flexible Heteroepitaxy of NiO Coated AZO Nanorods Arrays on Muscovites for Enhanced Energy Storage Application
(1970-01-01)
Van-Qui Le
;
Phuoc-Anh Le
;
Wu, Shu-Chi
;
Lai, Yu-Hong
;
Lin, Yan-Gu
Transparent flexible energy storage devices are considered as important chains in the next-generation, which are able to store and supply energy for electronic devices. Here, aluminum-doped zinc oxide (AZO) nanorods (NRs) and nickel oxide (NiO)-coated AZO NRs on muscovites are fabricated by a radio frequency (RF) magnetron sputtering deposition method. Interestingly, AZO NRs and AZO/NiO NRs are excellent electrodes for energy storage application with high optical transparency, high conductivity, large surface area, stability under compressive and tensile strain down to a bending radius of 5 mm with 1000 bending cycles. The obtained symmetric solid-state supercapacitors based on these electrodes exhibit good performance with a large areal specific capacitance of 3.4 mF cm(-2), long cycle life 1000 times, robust mechanical properties, and high chemical stability. Furthermore, an AZO/NiO//Zn battery based on these electrodes is demonstrated, yielding a discharge capacity of 195 mAh g(-1) at a current rate of 8 A g(-1) and a discharge capacity of over 1000 cycles with coulombic efficiency to 92%. These results deliver a concept of opening a new opportunity for future applications in transparent flexible energy storage.
Observing topotactic phase transformation and resistive switching behaviors in low power SrCoOx memristor
(2020-06-01)
Lo, Hung-Yang
;
Yang, Chih-Yu
;
Huang, Guan-Ming
;
Huang, Chih-Yang
;
Chen, Jui-Yuan
Recently, complex oxides have been shown to be promising candidate in dielectric materials of resistive random access memory (RRAM). However, the detailed switching information of complex oxide RRAM is still insufficient, and direct observation of the whole switching process is required to figure out the mechanism. In this study, we deposited SrCoOx (SCO) on a niobium-doped SrTiO3 substrate as the dielectric layer via pulsed laser deposition (PLD). The novel SCO device possesses excellent RRAM properties, high cycling endurance, a long data retention time, and uniform distributions of the high resistance state (HRS) and low resistance state (LRS) resistance and Set/Reset voltage. Furthermore, the switching mechanism was investigated by using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM), which showed that the switching behavior resulted from the topotactic phase transformation. In addition, the whole switching process was observed through in situ TEM, and the results strengthened the findings of the ex situ experiment. The discussion of this switching behavior provides support for a novel aspect of the RRAM switching mechanism and also a new option for the dielectric material in RRAM.
Epitaxial Yttria-Stabilized Zirconia on Muscovite for Flexible Transparent Ionic Conductors
(2018-12-01)
Wu, Ping-Chun
;
Lin, Yu-Pin
;
Juan, Yung-Hsiang
;
Wang, Yao-Ming
;
Do Thi-Hien
The advantages of ionic conductors have attracted great interest worldwide because they can fit the requirements that standard electrical conductors struggle to meet. Yttria-stabilized zirconia (YSZ) is the most common ionic conductor for various practical applications. In this study, in order to bring ionic conductors into the field of soft technology, transparent YSZ films with superior mechanical flexibility were epitaxially grown on a muscovite substrate by pulsed-laser deposition. The epitaxial relationship between YSZ and muscovite has been well established, indicating a high-crystallinity thin film. The heterostructure of YSZ/muscovite exhibits excellent ionic conductivity with great mechanical flexibility. The smallest bending radius of this heterostructure that can be achieved is similar to 10 mm with excellent mechanical cyclabilty (>800 cycles) and stability (>10(5) s), serving as a new platform to fabricate highly flexible ionic conductors.
Effects of pillar size modulation on the magneto-structural coupling in self-assembled BiFeO3-CoFe2O4 heteroepitaxy
(2020-01-21)
Amrillah, Tahta
;
Chen, Yu-Xun
;
My Ngoc Duong
;
Abdussalam, Wildan
;
Simanjuntak, Firman Mangasa
The magneto-structural coupling of BiFeO3 (BFO)-CoFe2O4 (CFO)/LaAlO3 (LAO) heteroepitaxy with various lateral sizes of CFO pillars embedded in a BFO matrix was investigated. A structural phase transformation of the BFO matrix was observed when the pillar size of CFO was increased to exceed 200 nm. Such structural transformation led to modification of magneto-elastic coupling behavior and magnetic anisotropy in the BFO-CFO/LAO system. The flexibility of tuning the pillar size of CFO, and hence, the strain and interfacial effect on the multiferroic system have significant application implications in these functional oxide nanocomposites.
Topological Hall Effect in Single Thick SrRuO3 Layers Induced by Defect Engineering
(1970-01-01)
Wang, Changan
;
Chang, Ching-Hao
;
Herklotz, Andreas
;
Chen, Chao
;
Ganss, Fabian
The topological Hall effect (THE) has been discovered in ultrathin SrRuO3 (SRO) films, where the interface between the SRO layer and another oxide layer breaks the inversion symmetry resulting in the appearance of THE. Thus, THE only occurs in ultrathin SRO films of several unit cells. In addition to employing a heterostructure, the inversion symmetry can be broken intrinsically in bulk SRO by introducing defects. In this study, THE is observed in 60-nm-thick SRO films, in which defects and lattice distortions are introduced by helium ion irradiation. The irradiated SRO films exhibit a pronounced THE in a wide temperature range from 5 to 80 K. These observations can be attributed to the emergence of Dzyaloshinskii-Moriya interaction as a result of artificial inversion symmetry breaking associated with the lattice defect engineering. The creation and control of the THE in oxide single layers can be realized by ex situ film processing. Therefore, this work provides new insights into the THE and illustrates a promising strategy to design novel spintronic devices.
Mechanically tunable exchange coupling of Co/CoO bilayers on flexible muscovite substrates
(2020-02-07)
Thai Duy Ha
;
Yen, Min
;
Lai, Yu-Hong
;
Kuo, Chang-Yang
;
Chen, Chien-Te
The employment of flexible muscovite substrates has given us the feasibility of applying strain to heterostructures dynamically by mechanical bending. In this study, this novel approach is utilized to investigate strain effects on the exchange coupling in ferromagnetic Co and anti-ferromagnetic CoO (Co/CoO) bilayers. Two different Co/CoO bilayer heterostructures were grown on muscovite substrates by oxide molecular beam epitaxy, with the CoO layer being purely (111)- and (100)-oriented. The strain-dependent exchange coupling effect can only be observed on Co/CoO(100)/mica but not on Co/CoO(111)/mica. The origin of this phenomenon is attributed to the anisotropic spin re-orientation induced by mechanical bending. The strain-dependent magnetic anisotropy of the bilayers determined by anisotropic magnetoresistance measurements confirms this conjecture. This study elucidates the fundamental understanding of how magnetic exchange coupling can be tuned by externally applied strain via mechanical bending and, hence, provides a novel approach for implementing flexible spintronic devices.
Self-assembled gold nanostructures in complex oxide thin films
(2020-01-01)
Wang, Hongliang
;
Yen, Min
;
Er, Xiaokuo
;
Liu, Pingping
;
Wan, Farong
Recently, noble metal-complex oxide nanocomposites with a high interface-to-volume ratio have attracted considerable interest for their potential applications in advanced devices. In this work, Nb:SrTiO3 epitaxial thin films embedded with different ratios of Au nanophase were fabricated using pulsed laser deposition. Detailed heterostructures at an atomic scale have been investigated based on advanced transmission electron microscopy. The results reveal that the pattern tunability of Au nanostructures can be realized by controlling the volume ratios between Au and Nb:SrTiO3, resulting in the manipulation of absorption characteristics in the visible light region. It is suggested that elastic energy and surface energy anisotropy are important factors to control the growth of the present Au/Nb:SrTiO3 heterostructures. This work offers a desirable platform to design nano composites with novel optical properties.
Graphene-Transition Metal Dichalcogenide Heterojunctions for Scalable and Low-Power Complementary Integrated Circuits
(2020-01-01)
Yeh, Chao-Hui
;
Liang, Zheng-Yong
;
Lin, Yung-Chang
;
Chen, Hsiang-Chieh
;
Fan, Ta
The most pressing barrier for the development of advanced electronics based on two-dimensional (2D) layered semiconductors stems from the lack of site-selective synthesis of complementary n- and p-channels with low contact resistance. Here, we report an in-plane epitaxial route for the growth of interlaced 2D semiconductor monolayers using chemical vapor deposition with a gas-confined scheme, in which patterned graphene (Gr) serves as a guiding template for site-selective growth of Gr-WS2-Gr and Gr-WSe2-Gr heterostructures. The Gr/2D semiconductor interface exhibits a transparent contact with a nearly ideal pinning factor of 0.95 for the n-channel WS2 and 0.92 for the p-channel WSe2. The effective depinning of the Fermi level gives an ultralow contact resistance of 0.75 and 1.20 k Omega.mu m for WS2 and WSe2, respectively. Integrated logic circuits including inverter, NAND gate, static random access memory, and five-stage ring oscillator are constructed using the complementary Gr-WS2-Gr-WSe2-Gr heterojunctions as a fundamental building block, featuring the prominent performance metrics of high operation frequency (>0.2 GHz), low-power consumption, large noise margins, and high operational stability. The technology presented here provides a speculative look at the electronic circuitry built on atomic-scale semiconductors in the near future.

學術出版;;Publications

Browse

Filters

Settings

Sort By

Results per page

🏛️國立陽明交通大學機構典藏

Search Results