1 |
Experimental and theoretical studies of electronic and mechanical properties of two-dimensional (2D) WSe₂Zhang, Rui January 2018 (has links)
Two-dimensional (2D) transition metal dichalcogenides (TMDs) with intrinsic band gaps are considered to be prospective alternatives for graphene in the applications of emerging nano-semiconductor devices. As a significant member of the TMDs family, WSe₂ with superior optical properties attracts increasing attention, especially in the optoelectronics. In this thesis, the electronic and mechanical properties of 2D WSe₂ have been studied experimentally and theoretically. Firstly, the fabrication of substrate-supported and suspended pre-patterned WSe₂ FETs with the low-cost optical lithography and vapour HF etching technology have been realised. The subsequent electrical measurement of the fabricated WSe₂ FETs indicates that the WSe₂/dielectric interface can affect the electrical performance of 2D WSe₂ negatively. To gain more insights on the impact of field-effect on 2D WSe₂, first-principle calculations have been conducted in this research to study the evolutions of the crystal structure, electronic band structure, conductive channel size, and electrical transport property of WSe2 under various levels of field-effect. Furthermore, a layer thinning and chemical doping method of 2D WSe₂ by vapour XeF₂ exposure featured with good air-stability, scalability, and controllability has been developed to enable the layer engineering of 2D WSe₂ and integration of 2D WSe₂ to logic circuits, solar cells, and light-emitting diodes (LED). The thinning and doping mechanism has been investigated with a combination of Raman spectroscopy, photoluminescence (PL) spectroscopy, and Xray photoelectron spectroscopy (XPS) characterization techniques. Afterwards, the inplane elastic properties (including the Young's modulus, breaking strain, and etc.) of 2D WSe₂ have been measured with nanoindentation experiments implemented by atomic force microscopy (AFM). The results prove the suitability of 2D WSe₂ in the applications of flexible devices and nanoelectromechanical systems (NEMS) operating in the audio resonance frequency, such as acoustic sensors and loudspeakers. To provide a comprehensive understanding of the strain engineering of 2D WSe₂, the strain induced variations of the crystal structure, electronic band structure, and electrical transport property of 2D WSe₂ have been further studied with first-principle calculations, which paves the way for the performance tuning of 2D WSe₂ devices via strain and applications of 2D WSe₂ in strain sensors.
|
2 |
Experimental and Theoretical Studies on Unique Reactivities of Nickel Catalysts / ニッケル触媒固有の反応性に関する実験的・理論的研究Takahashi, Toshifumi 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第23213号 / 工博第4857号 / 新制||工||1758(附属図書館) / 京都大学大学院工学研究科材料化学専攻 / (主査)教授 松原 誠二郎, 教授 杉野目 道紀, 教授 中尾 佳亮 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
|
3 |
Synthesis of Polar 1,2-Dimetalloalkenes and Their Application to Organic Synthesis / 極性1, 2-ジメタロアルケンの合成およびその有機合成への利用Takahashi, Fumiya 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第24438号 / 理博第4937号 / 新制||理||1705(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 依光 英樹, 教授 若宮 淳志, 教授 畠山 琢次 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
|
4 |
Development of Silylsilanolates as New Silylating Reagents / 新規シリル化剤シリルシラノラートの開発Yamagishi, Hiroki 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第24447号 / 理博第4946号 / 新制||理||1706(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 依光 英樹, 教授 若宮 淳志, 教授 畠山 琢次 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
|
5 |
Studies on π-extended helicenes / π拡張ヘリセンに関する諸研究Nakakuki, Yusuke 23 March 2022 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第23927号 / 工博第5014号 / 新制||工||1783(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 松田 建児, 教授 杉野目 道紀, 教授 生越 友樹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
|
6 |
Artificial Water Splitting: Ruthenium Complexes for Water OxidationDuan, Lele January 2011 (has links)
This thesis concerns the development and study of Ru-based water oxidation catalysts (WOCs) which are the essential components for solar energy conversion to fuels. The first chapter gives a general introduction about the field of homogenous water oxidation catalysis, including the catalytic mechanisms and the catalytic activities of some selected WOCs as well as the concerns of catalyst design. The second chapter describes a family of mononuclear Ru complexes [Ru(pdc)L3] (H2pdc = 2,6-pyridinedicarboxylic acid; L = pyridyl ligands) towards water oxidation. The negatively charged pdc2− dramatically lowers the oxidation potentials of Ru complexes, accelerates the ligand exchange process and enhances the catalytic activity towards water oxidation. A Ru aqua species [Ru(pdc)L2(OH2)] was proposed as the real catalyst. The third chapter describes the analogues of [Ru(terpy)L3]2+ (terpy = 2,2′:6′,2′′-terpyridine). Through the structural tailor, the ligand effect on the electrochemical and catalytic properties of these Ru complexes was studied. Mechanistic studies suggested that these Ru-N6 complexes were pre-catalysts and the Ru-aqua species were the real WOCs. The forth chapter describes a family of fast WOCs [Ru(bda)L2] (H2bda = 2,2′-bipyridine-6,6′-dicarboxylic acid). Catalytic mechanisms were thoroughly investigated by electrochemical, kinetic and theoretical studies. The main contributions of this work to the field of water oxidation are (i) the recorded high reaction rate of 469 s−1; (ii) the involvement of seven-coordinate Ru species in the catalytic cycles; (iii) the O-O bond formation pathway via direct coupling of two Ru=O units and (iv) non-covalent effects boosting up the reaction rate. The fifth chapter is about visible light-driven water oxidation using a three component system including a WOC, a photosensitizer and a sacrificial electron acceptor. Light-driven water oxidation was successfully demonstrated using our Ru-based catalysts. / QC 20110922
|
7 |
Synthesis of structurally controlled hyperbranched polymers through the design of new monomers with hierarchical reactivity / 反応性の序列を有するモノマー設計による構造制御された多分岐重合体の合成Lu, Yangtian 23 July 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22014号 / 工博第4626号 / 新制||工||1721(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 山子 茂, 教授 辻井 敬亘, 教授 竹中 幹人 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
|
8 |
Development of Silyl Groups Bearing Bulky Alkoxy Unit and Their Application to Organic Synthesis / 嵩高いアルコキシ部位を有するシリル基の開発と有機合成への利用Saito, Hayate 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第23027号 / 理博第4704号 / 新制||理||1675(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 依光 英樹, 教授 時任 宣博, 教授 若宮 淳志 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
|
9 |
Construction of interatomic potentials using large sets of DFT calculations and linear regression method / 網羅的第一原理計算と線形回帰を用いた原子間ポテンシャルの構築Takahashi, Akira 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20369号 / 工博第4306号 / 新制||工||1667(附属図書館) / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 田中 功, 教授 酒井 明, 教授 中村 裕之 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
|
10 |
Characterizing triplet azo biradical and corannulene- halogen complexes by laser flash photolysisLi, Qian January 2012 (has links)
No description available.
|
Page generated in 0.0856 seconds