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In situ synchrotron radiation studies of functional materials prepared through CVD techniques

CVD 技术制备功能材料的原位同步辐射研究

基本信息

批准号：
EP/G067937/1
负责人：
Ivan Parkin
金额：
$ 19.02万
依托单位：
University College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2009
资助国家：
英国
起止时间：
2009 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FG067937%2F1
关键词：
situ synchrotron radiation studies functional

项目摘要

Chemical vapour deposition is an enormously important technique for the formation of thin films. It is the most widely used coating technique in industry for coatings especially for the flat glass industry where it is used to make energy efficient and self cleaning coatings through to the glass bottle industry where it is used to make low friction coatings ( total value > 10B pa). It is also one of the key techniques used in microelectronics for the fabrication of integrated circuits. Despite its immense value the study of the formation of CVD films by in situ analysis has been surprisingly sparse. Typically films are studied after deposition and cool-down and not as they are grown. Some in situ measurements have been made especially by elipsometry, Raman, and reflectometry techniques. Direct measurements of the growth process by XRD or by EXAFS has been difficult to achieve because the samples are in thin-film form typically contain few atomic layers (1-100 nm thick) and construction of reactors cells that accommodate the CVD experiment and the source have proved exacting. The process is only possible with a brilliant light source such as that provided by a synchrotron. The ability to study what is happening during the initial growth phases in a CVD process will bring immense benefit to understanding the process and will enable better design and control of a CVD experiment. For example to determine the position of a dopant atom in a structure and relate this to functionality and to understand how preferred orientation and growth changes during a CVD process. This has societal benefits- for example low-energy window coatings (such as K-glass) prepared by CVD have three times better performance if grown with the optimum growth direction. The performance of ZnO thin films for use as a transparent oxide conductor is magnified if grown with a (1 0 0) orientation. The position of the nitrogen dopant atom within titanium dioxide in N-doped titania is greatly effected by CVD conditions and both substitutional and interstitial doping is seen. However only the interstitial doping is important in extending the band gap and making a visible light photocatalyst. Such a material could find widespread usage as an antimicrobial coating for use in hospitals (to reduce MRSA transmission) and also as a visible light photocatalysts that can be used for water splitting. To realize that potential to improve on existing materials the growth process needs to be studied in detail and the conditions developed and understood that lead only to interstitial N- doping. Such complex problems can now be tackled with the next generation of synchrotron sources such as ESRF and DIAMOND.

化学气相沉积是形成薄膜的一种非常重要的技术。它是工业中使用最广泛的涂层技术，特别是在平板玻璃行业，它被用来制造节能和自洁的涂层，一直到玻璃瓶行业，它被用来制造低摩擦涂层(总价值&gt；10B pa)。它也是微电子学中用于制造集成电路的关键技术之一。尽管它具有巨大的价值，但通过原位分析来研究CVD薄膜的形成却令人惊讶地稀少。通常，薄膜是在沉积和冷却之后研究的，而不是在生长过程中研究的。一些现场测量特别是通过椭圆偏振、拉曼和反射测量技术进行的。用X射线衍射仪或EXAFS直接测量生长过程一直很难实现，因为样品是薄膜形式的，通常包含很少的原子层(1-100 nm厚)，而且事实证明，容纳CVD实验和源的反应池的构造是严格的。只有在同步加速器提供的那种明亮的光源下，这一过程才有可能。能够研究在CVD过程的初始生长阶段发生了什么，将为理解该过程带来巨大的好处，并将使CVD实验能够更好地设计和控制。例如，确定掺杂剂原子在结构中的位置，并将其与功能联系起来，以及了解择优取向和生长在CVD过程中如何变化。这具有社会效益--例如，用化学气相沉积方法制备的低能窗口涂层(如K玻璃)，如果以最佳生长方向生长，其性能可提高三倍。以(100)择优取向生长的氧化锌薄膜作为透明氧化物导体的性能得到了放大。在N掺杂二氧化钛中，氮掺杂原子在二氧化钛中的位置受CVD条件的影响很大，既有代位掺杂，也有间隙掺杂。然而，只有间隙掺杂才是扩大禁带宽度和制备可见光催化剂的重要因素。这种材料可广泛用作医院使用的抗菌涂层(以减少MRSA的传播)，也可用作可见光催化剂，可用于分解水。为了实现改善现有材料的潜力，需要详细研究生长过程，开发和了解只导致间隙氮掺杂的条件。这种复杂的问题现在可以用下一代同步加速器源来解决，如ESRF和钻石。