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518 results on '"Ni, Chaoying"'

20. Band gap and band offset of Ga$_2$O$_3$ and (Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloys

Author

Wang, Tianshi, Li, Wei, Ni, Chaoying, and Janotti, Anderson

Subjects
Condensed Matter - Materials Science
Abstract

Ga$_2$O$_3$ and (Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloys are promising materials for solar-blind UV photodetectors and high-power transistors. Basic key parameters in the device design, such as band gap variation with alloy composition and band offset between Ga$_2$O$_3$ and (Al$_x$Ga$_{1-x}$)$_2$O$_3$, are yet to be established. Using density functional theory with the HSE hybrid functional, we compute formation enthalpies, band gaps, and band edge positions of (Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloys in the monoclinic ($\beta$) and corundum ($\alpha$) phases. We find the formation enthlapies of (Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloys are significantly lower than of (In$_x$Ga$_{1-x}$)$_2$O$_3$, and that (Al$_x$Ga$_{1-x}$)$_2$O$_3$ with $x$=0.5 can be considered as an ordered compound AlGaO$_3$ in the monoclinic phase, with Al occupying the octahedral sites and Ga occupying the tetrahedral sites. The direct band gaps of the alloys range from 4.69 to 7.03 eV for $\beta$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ and from 5.26 to 8.56 eV for $\alpha$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$. Most of the band offset of the (Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloy arises from the discontinuity in the conduction band. Our results are used to explain the available experimental data, and consequences for designing modulation-doped field effect transistors (MODFETs) based on (Al$_x$Ga$_{1-x}$)$_2$O$_3$/Ga$_2$O$_3$ are discussed.

Published
2018
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26. Microstructural Characteristics of Reaction-Bonded B4C/SiC Composite

Author

Wang, Tianshi, Ni, Chaoying, and Karandikar, Prashant

Subjects
Condensed Matter - Materials Science
Abstract

A detailed microstructural investigation was performed to understand structural characteristics of a reaction-bonded B$_4$C/SiC ceramic composite. The state-of-the-art focused ion beam & scanning electron microscopy (FIB/SEM) and transmission electron microscopy (TEM) revealed that the as-fabricated product consisted of core-rim structures with {\alpha}-SiC and $B_4$C cores surrounded by \beta-SiC and $B_4$C, respectively. In addition, plate-like \beta-SiC was detected within the $B_4$C rim. A phase formation mechanism was proposed and the analytical elucidation is anticipated to shed light on potential fabrication optimization and the property improvement of ceramic composites., Comment: 8 pages, TMS2016

Published
2016
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27. Thermal Transport Across Metal Silicide-Silicon Interfaces: An Experimental Comparison between Epitaxial and Non-epitaxial Interfaces

Author

Ye, Ning, Feser, Joseph P, Sadasivam, Sridhar, Fisher, Timothy S., Wang, Tianshi, Ni, Chaoying, and Janotti, Anderson

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Silicides are used extensively in nano- and microdevices due to their low electrical resistivity, low contact resistance to silicon, and their process compatibility. In this work, the thermal interface conductance of TiSi$_2$, CoSi$_2$, NiSi and PtSi are studied using time-domain thermoreflectance. Exploiting the fact that most silicides formed on Si(111) substrates grow epitaxially, while most silicides on Si(100) do not, we study the effect of epitaxy, and show that for a wide variety of interfaces there is no difference in the thermal interface conductance of epitaxial and non-epitaxial silicide/silicon interfaces. The effect of substrate carrier concentration is also investigated over a wide range of p- and n-type doping, and is found to be independent of carrier concentration, regardless of whether the interface is epitaxial and regardless of silicide type. In the case of epitaxial CoSi$_2$, a comparison of temperature dependant experimental data is made with two detailed computational models using (1) full-dispersion diffuse mismatch modeling (DMM) including the effect of near-interfacial strain and (2) an atomistic Green' function (AGF) approach that integrates near-interface changes in the interatomic force constants obtained through density functional perturbation theory. At temperatures above 100K, the AGF approach greatly underpredicts the CoSi$_2$ data, while the DMM prediction matches the data well. The full-dispersion DMM is also found to closely predict the experimentally observed temperature-dependent interface conductance for epitaxial NiSi/Si and non-epitaxial TiSi$_2$/Si interfaces. In the case of epitaxial PtSi/Si interfaces, full dispersion DMM significantly overpredicts the experimental data., Comment: 6 Figures, Accepted at Phys. Rev. B (Jan. 26, 2017)

Published
2016
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32. LncRNA-AC006129.1 reactivates a SOCS3-mediated anti-inflammatory response through DNA methylation-mediated CIC downregulation in schizophrenia

Author

Ni, Chaoying, Jiang, Wei, Wang, Zhongju, Wang, Zhuo, Zhang, Jian, Zheng, Xianzhen, Liu, Zelin, Ou, Haiyan, Jiang, Tingyun, Liang, Wenquan, Wu, Fengchun, Li, Qiyang, Hou, Yu, Yang, Qiong, Guo, Bo, Liu, Sihan, Li, Shuyun, Li, Shufen, Yang, Ence, Zhu, Xin-Hong, Huang, Xingbing, Wen, Zhexing, and Zhao, Cunyou

Published
2021
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37. Efficient defect-driven cation exchange beyond the nanoscale semiconductors toward antibacterial functionalization

Author

Polivtseva, Svetlana, primary, Volobujeva, Olga, additional, Kuznietsov, Ivan, additional, Kaupmees, Reelika, additional, Danilson, Mati, additional, Krustok, Jüri, additional, Molaiyan, Palanivel, additional, Hu, Tao, additional, Lassi, Ulla, additional, Klopov, Mihhail, additional, van Gog, Heleen, additional, van Huis, Marijn A., additional, Kaur, Harleen, additional, Ivask, Angela, additional, Rosenberg, Merilin, additional, Gathergood, Nicholas, additional, Ni, Chaoying, additional, and Grossberg-Kuusk, Maarja, additional

Published
2024
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46. Demonstration of mid-infrared waveguide photonic crystal cavities

Author

Lin, Hongtao, Li, Lan, Deng, Fei, Ni, Chaoying, Danto, Sylvain, Musgraves, J. David, Richardson, Kathleen, and Hu, Juejun

Subjects
Physics - Optics
Abstract

We have demonstrated what we believe to be the first waveguide photonic crystal cavity operating in the mid-infrared. The devices were fabricated from Ge23Sb7S70 chalcogenide glass on CaF2 substrates by combing photolithographic patterning and focus ion beam milling. The waveguide-coupled cavities were characterized using a fiber end fire coupling method at 5.2 {\mu}m wavelength, and a loaded quality factor of ~ 2,000 was measured near the critical coupling regime., Comment: 4 pages, 5 figures

Published
2013
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49. Pyrite-assisted degradation of methoxychlor by laccase immobilized on Fe3S4/earthworm-like mesoporous SiO2.

Author

Yang, Jiaqi, Yang, Yuxiang, Chang, Ziling, Huang, Yan, Yuan, Hongming, Zhao, Yi, Liu, Xiangnong, and Ni, Chaoying

Subjects
METHOXYCHLOR, PYRITES, LACCASE, MASS spectrometry, ELECTRON donors, ACTIVATION energy, THERMAL stability
Abstract

Laccase immobilized and cross-linked on Fe3S4/earthworm-like mesoporous SiO2 (Fe3S4/EW-mSiO2) was used to degrade methoxychlor (MXC) in aqueous environments. The effects of various parameters on the degradation of MXC were determined using free and immobilized laccase. Immobilization improved the thermal stability and reuse of laccase significantly. Under the conditions of pH 4.5, temperature 40 °C, and reaction time 8 h, the degradation rate of MXC by immobilized laccase reached a maximum value of 40.99% and remained at 1/3 of the original after six cycles. The excellent degradation performance of Fe3S4/EW-mSiO2 was attributable to the pyrite (FeS2) impurity in Fe3S4, which could act as an electron donor in reductive dehalogenation. Sulfide groups and Fe2+ reduced the activation energy of the system resulting in pyrite-assisted degradation of MXC. The degradation mechanism of MXC in aqueous environments by laccase immobilized on Fe3S4/EW-mSiO2 was determined via mass spectroscopy of the degradation products. This study is a new attempt to use pyrite to support immobilized laccase degradation. [ABSTRACT FROM AUTHOR]

Published
2024
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