{"title":"Exploring localisation of the Sustainable Development Goals : Focusing on municipal organisations in a Swedish context","authors":"Venus Krantz","doi":"10.3384/9789179294847","DOIUrl":"https://doi.org/10.3384/9789179294847","url":null,"abstract":"","PeriodicalId":303036,"journal":{"name":"Linköping Studies in Science and Technology. Licentiate Thesis","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126358053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The semiconductor tritantalum pentanitride (Ta3N5) is a promising green-energy material for photoelectrolyzing water to produce oxygen and hydrogen owing to its proper bandgap of 2.0 ± 0.2 eV and band positions to redox potential of water. Compare with the conventional setup of water splitting, such as TiO2, Fe2O3, Cu2O, and WO3, the Ta3N5 shows a proper band gap, which leads to a theoretical efficiency as high as 15.9%. However, the complexity of the Ta-N system and the metastability of the Ta3N5 result in the limited research of the growth of high quality stoichiometric Ta3N5. Conventionally, the two-step growth of oxidation and nitridation of a metal Ta using thermal annealing in oxygen and ammonia environment is used to produce the Ta3N5. However, the amount of incorporated oxygen in the Ta3N5 samples and film’s thickness and interface are hardly to be controlled, and the use of ammonia as the nitridation gas is harmful to the environment. Hence, in this thesis work, the reactive magnetron sputtering is used to synthesis the Ta3N5, which demonstrates some advantages, such as possibility to grow on a substrate with nanostructure on the surface, a simplification of growth process, usage of environmental-friendly reactive gas, and even scaling up to the industrial application. The thesis presents a successful growth of orthorhombic Ta3N5-type Ta-O-N compound thin films on Si and sapphire substrates, specifically Ta3-xN5-yOy, using reactive magnetron sputtering with a gas mixture of Ar, N2, and O2. In the deposition process, the total working pressure was increasing from 5 to 40 mTorr, while keeping same partial pressure ratio (Ar: N2: O2 = 3: 2: 0.1). When the total pressure in the region between 5-30 mTorr, a low-degree fiber-textural Ta3-xN5-yOy films were grown. In addition, with the characterization of elastic recoil detection analysis (ERDA), the atomic fraction of O, N, and Ta of as-grown Ta3-xN5-yOy films were found varying from 0.02 to 0.15, 0.66 to 0.54, and 0.33 to 0.31, respectively, which leads to a b-lattice constant decrease around 1.3 %, shown in X-ray diffraction (XRD) results. For a total working pressure up to 40 mTorr, an amorphous O-rich Ta-O-N compound film was formed mixed with non-stoichiometric TaON and Ta2O5, which further raised the oxygen atomic fraction to ~0.48. The increasing total working pressure results in an increasing band gap from 2.22 to 2.66 eV of Ta3-xN5-yOy films, and further increasing to around 2.96 eV of O-rich Ta-O-N compound films. The mechanism of increasing oxygen atomic fraction in the film is founded correlated with the forming oxide on the Ta target surface during the deposition process due to the strong reactivity of O to Ta by the characterization of optical emission spectroscopy (OES). Moreover, the sputter yield was reduced due to the target poisoning, and which is evidenced by both plasma analysis and depth profile from ERDA. A further studies with the deposition parameters for nearly pure T
半导体五氮化三钽（Ta3N5）的带隙为 2.0 ± 0.2 eV，其带位与水的氧化还原电位一致，因此是一种很有前途的光电解水产生氧气和氢气的绿色能源材料。与传统的水分离装置（如 TiO2、Fe2O3、Cu2O 和 WO3）相比，Ta3N5 具有合适的带隙，因此理论效率高达 15.9%。然而，Ta-N 体系的复杂性和 Ta3N5 的易陨性导致对高质量全等值 Ta3N5 生长的研究十分有限。传统的方法是在氧气和氨气环境中通过热退火将金属 Ta 氧化和氮化两步生长来生产 Ta3N5。然而，Ta3N5 样品中的含氧量、薄膜厚度和界面很难控制，而且使用氨气作为氮化气体对环境有害。因此，本论文采用反应磁控溅射法合成 Ta3N5，这种方法具有一些优势，例如可以在表面具有纳米结构的基底上生长，简化了生长过程，使用环保的反应气体，甚至可以扩展到工业应用。论文介绍了利用反应磁控溅射技术，在 Ar、N2 和 O2 混合气体的作用下，在硅基底和蓝宝石基底上成功生长出正交的 Ta3N5 型 Ta-O-N 化合物薄膜，特别是 Ta3-xN5-yOy。在沉积过程中，总工作压力从 5 mTorr 增加到 40 mTorr，同时保持相同的分压比（Ar: N2: O2 = 3: 2: 0.1）。当总压力在 5-30 mTorr 之间时，生长出了低度纤维纹理的 Ta3-xN5-yOy 薄膜。此外，通过弹性反冲检测分析（ERDA），发现生长的 Ta3-xN5-yOy 薄膜中 O、N 和 Ta 的原子分数分别从 0.02 到 0.15、0.66 到 0.54 和 0.33 到 0.31 不等，这导致 b-晶格常数下降了约 1.3%，如 X 射线衍射（XRD）结果所示。当总工作压力达到 40 mTorr 时，会形成一层无定形的富 O Ta-O-N 化合物薄膜，其中混有非均相的 TaON 和 Ta2O5，这进一步将氧原子分数提高到 ~0.48。总工作压力的增加导致 Ta3-xN5-yOy 薄膜的带隙从 2.22 eV 增加到 2.66 eV，富 O 的 Ta-O-N 化合物薄膜的带隙进一步增加到约 2.96 eV。根据光学发射光谱（OES）的表征，薄膜中氧原子分数增加的机制与沉积过程中在 Ta 靶表面形成氧化物有关，因为 O 对 Ta 有很强的反应性。此外，由于靶中毒，溅射产率降低，等离子体分析和 ERDA 的深度剖面都证明了这一点。使用 c 轴取向的 Al2O3 基底，对接近纯净的 Ta3N5 薄膜（氧原子分数约为 2%）的沉积参数进行了进一步研究。研究发现，Ta3N5 的生长需要 Ta2O5 种子层和少量氧气。X 射线光电子能谱（XPS）证明，在没有种子层和氧气的帮助下，只能生长出金属 TaN 相，即 和 TaN 的混合物或 -TaN。此外，Ta3N5 相为主的薄膜的结构和相纯度与 Ta2O5 种子层的厚度高度相关。随着种子层厚度从 5 纳米、9 纳米到 17 纳米的增加，生长出的薄膜成分从 111 取向的 -TaN 混合 c 轴取向的 Ta3N5、c 轴取向的 Ta3N5 到多晶的 Ta3N5。此外，在掠入射几何条件下的方位角 -scan 表明，c 轴取向的 Ta3N5 中含有三变取向的外延畴，其中 a 和 b 平面与 c 轴取向的 Al2O3 的 m 和 a 平面平行。通过密度泛函理论（DFT）的模拟，在计算拓扑和能量选择标准之间的相互作用后，发现通过引入少量氧，可以促进正交态 Ta2O5（β-Ta2O5）薄种子层的生长。在上述标准的共同作用下，这种已经生长的 Ta2O5 种子层有利于正方体 Ta3N5 相的生长。因此，c 轴取向的 Ta3N5 在 c 轴取向的 Al2O3 上的畴外延生长机制归因于相似的原子排列 Ta3N5(001) 和 β-Ta2O5(201)，薄膜/种子层和种子层/基底的界面分别存在 2.6% 和 4.5% 左右的小晶格失配，以及相关材料之间有利的能量相互作用。
{"title":"Metastable orthorhombic Ta3N5 thin films grown by magnetron sputter epitaxy","authors":"Jui-Che Chang","doi":"10.3384/9789179295004","DOIUrl":"https://doi.org/10.3384/9789179295004","url":null,"abstract":"The semiconductor tritantalum pentanitride (Ta3N5) is a promising green-energy material for photoelectrolyzing water to produce oxygen and hydrogen owing to its proper bandgap of 2.0 ± 0.2 eV and band positions to redox potential of water. Compare with the conventional setup of water splitting, such as TiO2, Fe2O3, Cu2O, and WO3, the Ta3N5 shows a proper band gap, which leads to a theoretical efficiency as high as 15.9%. However, the complexity of the Ta-N system and the metastability of the Ta3N5 result in the limited research of the growth of high quality stoichiometric Ta3N5. Conventionally, the two-step growth of oxidation and nitridation of a metal Ta using thermal annealing in oxygen and ammonia environment is used to produce the Ta3N5. However, the amount of incorporated oxygen in the Ta3N5 samples and film’s thickness and interface are hardly to be controlled, and the use of ammonia as the nitridation gas is harmful to the environment. Hence, in this thesis work, the reactive magnetron sputtering is used to synthesis the Ta3N5, which demonstrates some advantages, such as possibility to grow on a substrate with nanostructure on the surface, a simplification of growth process, usage of environmental-friendly reactive gas, and even scaling up to the industrial application. The thesis presents a successful growth of orthorhombic Ta3N5-type Ta-O-N compound thin films on Si and sapphire substrates, specifically Ta3-xN5-yOy, using reactive magnetron sputtering with a gas mixture of Ar, N2, and O2. In the deposition process, the total working pressure was increasing from 5 to 40 mTorr, while keeping same partial pressure ratio (Ar: N2: O2 = 3: 2: 0.1). When the total pressure in the region between 5-30 mTorr, a low-degree fiber-textural Ta3-xN5-yOy films were grown. In addition, with the characterization of elastic recoil detection analysis (ERDA), the atomic fraction of O, N, and Ta of as-grown Ta3-xN5-yOy films were found varying from 0.02 to 0.15, 0.66 to 0.54, and 0.33 to 0.31, respectively, which leads to a b-lattice constant decrease around 1.3 %, shown in X-ray diffraction (XRD) results. For a total working pressure up to 40 mTorr, an amorphous O-rich Ta-O-N compound film was formed mixed with non-stoichiometric TaON and Ta2O5, which further raised the oxygen atomic fraction to ~0.48. The increasing total working pressure results in an increasing band gap from 2.22 to 2.66 eV of Ta3-xN5-yOy films, and further increasing to around 2.96 eV of O-rich Ta-O-N compound films. The mechanism of increasing oxygen atomic fraction in the film is founded correlated with the forming oxide on the Ta target surface during the deposition process due to the strong reactivity of O to Ta by the characterization of optical emission spectroscopy (OES). Moreover, the sputter yield was reduced due to the target poisoning, and which is evidenced by both plasma analysis and depth profile from ERDA. A further studies with the deposition parameters for nearly pure T","PeriodicalId":303036,"journal":{"name":"Linköping Studies in Science and Technology. Licentiate Thesis","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127471795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Exploring Change toward Sustainability in Established Business Models","authors":"Arvid Wahlman","doi":"10.3384/9789179294434","DOIUrl":"https://doi.org/10.3384/9789179294434","url":null,"abstract":"","PeriodicalId":303036,"journal":{"name":"Linköping Studies in Science and Technology. Licentiate Thesis","volume":"413 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133761099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Developing Microscopic Traffic Simulation Models for the Transition Towards Automated Driving","authors":"I. Postigo","doi":"10.3384/9789179294397","DOIUrl":"https://doi.org/10.3384/9789179294397","url":null,"abstract":"","PeriodicalId":303036,"journal":{"name":"Linköping Studies in Science and Technology. Licentiate Thesis","volume":"91 42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128821786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Calibration of Urban Network Capacities","authors":"Guang-Hao Wei","doi":"10.3384/9789179293765","DOIUrl":"https://doi.org/10.3384/9789179293765","url":null,"abstract":"","PeriodicalId":303036,"journal":{"name":"Linköping Studies in Science and Technology. Licentiate Thesis","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126821616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mode choice modelling of long-distance passenger transport based on mobile phone network data","authors":"Angelica Andersson","doi":"10.3384/9789179293604","DOIUrl":"https://doi.org/10.3384/9789179293604","url":null,"abstract":"","PeriodicalId":303036,"journal":{"name":"Linköping Studies in Science and Technology. Licentiate Thesis","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130124280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Construction transport efficiency from the perspective of Main Contractor and Transporter","authors":"F. Naz","doi":"10.3384/9789179292744","DOIUrl":"https://doi.org/10.3384/9789179292744","url":null,"abstract":"","PeriodicalId":303036,"journal":{"name":"Linköping Studies in Science and Technology. Licentiate Thesis","volume":"284 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131416589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Exploring Data-Driven Methods to Enhance Usability of Design Optimization","authors":"E. Gustafsson","doi":"10.3384/9789179292782","DOIUrl":"https://doi.org/10.3384/9789179292782","url":null,"abstract":"","PeriodicalId":303036,"journal":{"name":"Linköping Studies in Science and Technology. Licentiate Thesis","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133136541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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