扫描隧道显微镜诱导发光技术在纳米表征中的应用
发布时间：2018-08-27 11:49
【摘要】：如何在单分子尺度上揭示纳米结构的光电特性是纳米光电子学研究中的核心科学问题。扫描隧道显微镜(STM)具有单原子级别的实空间表征能力,极大地提高了人类认识和操控微观世界的能力。将STM与光学检测技术结合起来的STM诱导发光技术(STML),可以把高空间分辨的形貌表征技术与高灵敏的能量、时间分辨的光学检测技术结合起来,不仅提高了 STM的化学分析能力,而且还可以帮助我们研究纳米结构-固体界面以及纳米结构在特定纳米环境中的跃迁及其相关的动力学过程。本论文的主要工作就是发展并完善了与超高真空低温STM联用的STML技术,实现了单分子电致荧光,并利用单分子电致荧光稳态成像技术表征了分子质子转移的瞬态中间态,为拓展STML技术在纳米光源、光电集成、以及化学反应动态学等方面的应用奠定了基础。本论文分为四个部分:第一章,我们首先简要介绍了 STM以及表面等离激元(surface plasmons)的物理背景和研究现状。随后,我们详细介绍了 STM诱导发光技术及其研究现状。最后,我们简单地介绍了本工作中所使用的相关实验仪器。第二章,我们研究了 STM诱导的单个空心酞菁分子(H_2Pc)的电致荧光现象。利用NaCl薄膜作为脱耦合层,我们成功地实现了源自H_2Pc分子HOMO-LUMO能级间辐射跃迁的单分子电致荧光。通过分析电致发光光谱随纳腔等离激元模式的变化,我们讨论了纳腔等离激元在STM诱导分子发光中的重要作用,并结合隧穿电导谱讨论了单分子电致发光机理。我们还利用STM操纵技术展示了隧道结中单分子发光的可调性。第三章,我们研究了单个空心酞菁分子内的质子转移过程。我们利用纳腔等离激元共振增强,提高了单个H_2Pc分子的自发辐射速率,并探测到单个H_2Pc分子的热荧光。结合光谱成像技术,我们首次在单分子尺度上直接观察到分子内质子转移过程中中间态的存在。我们的结果不仅可以帮助人们更加深刻地理解卟啉酞菁类分子内的质子转移过程,而且还提供了一种新的利用非驰豫荧光成像技术探索表面上分子动力学过程的新思路与新方法。第四章,我们对现有的STML探测模式进行了拓展。首先,为了表征纳米结构的近场光学特性,我们发展了近场收集模式。我们使用尖端镀有半导体透明导电膜(ITO)的光纤探针作为STM针尖,研究了 GaAs(110)表面以及吸附在GaAs(110)表面的H2TBPP分子的STM诱导发光现象,初步实现了近场探测。其次,为了获取隧道结中单个分子辐射的角向分布特性和偏振特性,进而分析隧道结中分子偶极取向等重要信息,我们发展了低温超高真空STML的样品背面的光子收集系统,目前已初步实现了后焦面成像探测,为后续单分子光源和光电集成的研究奠定了基础。
[Abstract]:How to reveal the photoelectric properties of nanostructures on a single molecular scale is a key scientific issue in the study of nano-optoelectronics. The scanning tunneling microscope (STM) (STM) has the ability to represent the real space at the single atomic level, which greatly improves the ability of human beings to understand and manipulate the microcosm. STM induced luminescence (STML), which combines STM with optical detection, not only improves the ability of chemical analysis of STM, but also combines high spatial resolution morphology characterization technology with high sensitive energy and time-resolved optical detection technology. It can also help us to study the nanostructure-solid interface and the transition of nanostructures in specific nanoscale environments and the related kinetic processes. The main work of this thesis is to develop and perfect the STML technology combined with ultra-high vacuum low temperature (STM) to realize single molecule electrofluorescence, and to characterize the transient intermediate state of molecular proton transfer by using monolayer electrofluorescence steady-state imaging technique. It lays a foundation for the application of STML technology in nanometer light source, optoelectronic integration, chemical reaction dynamics and so on. This thesis is divided into four parts: in Chapter 1, we briefly introduce the physical background and research status of STM and (surface plasmons). Then, we introduce the STM induced luminescence technology and its research status in detail. Finally, we briefly introduce the related experimental instruments used in this work. In chapter 2, we study the electroluminescence of a single hollow phthalocyanine molecule (H_2Pc) induced by STM. Using the NaCl film as the decoupling layer, we have successfully realized the monolayer electroluminescence from the radiation transition between the HOMO-LUMO energy levels of the H_2Pc molecule. By analyzing the variation of electroluminescence spectra with the mode of nanoscale isophosphors, we discuss the important role of nanoscale isophosphors in STM induced molecular luminescence, and discuss the mechanism of monolayer electroluminescence in combination with tunneling conductance spectroscopy. We also demonstrate the tunability of monolayer luminescence in tunnel junctions by using STM manipulation technique. In chapter 3, we study the proton transfer process in a single hollow phthalocyanine molecule. The spontaneous emission rate of a single H_2Pc molecule is increased and the thermal fluorescence of a single H_2Pc molecule is detected. In combination with spectral imaging techniques, we observed the presence of intermediate states in intramolecular proton transfer processes on a single molecular scale for the first time. Our results not only help people understand the proton transfer process in porphyrin phthalocyanines, It also provides a new idea and a new method to explore the molecular dynamics process on the surface by using the non-relaxation fluorescence imaging technology. In chapter 4, we extend the existing STML detection mode. First, in order to characterize the near-field optical properties of nanostructures, we developed a near-field collection model. The STM induced luminescence of GaAs (110) and H2TBPP molecules adsorbed on the surface of GaAs (110) and on the surface of GaAs (110) have been studied by using the fiber probe coated with semiconductor transparent conductive film (ITO) as the tip of the STM needle. The near field detection has been preliminarily realized. Secondly, in order to obtain the angular distribution and polarization characteristics of single molecule radiation in tunnel junctions, and to analyze the important information of molecular dipole orientation in tunnel junctions, we developed a photon collection system on the back of samples of ultra-high vacuum STML at low temperature. At present, the detection of rear focal plane imaging has been preliminarily realized, which lays a foundation for the further study of monolayer light source and optoelectronic integration.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TH742;TB383.1
本文编号：2207187
[Abstract]:How to reveal the photoelectric properties of nanostructures on a single molecular scale is a key scientific issue in the study of nano-optoelectronics. The scanning tunneling microscope (STM) (STM) has the ability to represent the real space at the single atomic level, which greatly improves the ability of human beings to understand and manipulate the microcosm. STM induced luminescence (STML), which combines STM with optical detection, not only improves the ability of chemical analysis of STM, but also combines high spatial resolution morphology characterization technology with high sensitive energy and time-resolved optical detection technology. It can also help us to study the nanostructure-solid interface and the transition of nanostructures in specific nanoscale environments and the related kinetic processes. The main work of this thesis is to develop and perfect the STML technology combined with ultra-high vacuum low temperature (STM) to realize single molecule electrofluorescence, and to characterize the transient intermediate state of molecular proton transfer by using monolayer electrofluorescence steady-state imaging technique. It lays a foundation for the application of STML technology in nanometer light source, optoelectronic integration, chemical reaction dynamics and so on. This thesis is divided into four parts: in Chapter 1, we briefly introduce the physical background and research status of STM and (surface plasmons). Then, we introduce the STM induced luminescence technology and its research status in detail. Finally, we briefly introduce the related experimental instruments used in this work. In chapter 2, we study the electroluminescence of a single hollow phthalocyanine molecule (H_2Pc) induced by STM. Using the NaCl film as the decoupling layer, we have successfully realized the monolayer electroluminescence from the radiation transition between the HOMO-LUMO energy levels of the H_2Pc molecule. By analyzing the variation of electroluminescence spectra with the mode of nanoscale isophosphors, we discuss the important role of nanoscale isophosphors in STM induced molecular luminescence, and discuss the mechanism of monolayer electroluminescence in combination with tunneling conductance spectroscopy. We also demonstrate the tunability of monolayer luminescence in tunnel junctions by using STM manipulation technique. In chapter 3, we study the proton transfer process in a single hollow phthalocyanine molecule. The spontaneous emission rate of a single H_2Pc molecule is increased and the thermal fluorescence of a single H_2Pc molecule is detected. In combination with spectral imaging techniques, we observed the presence of intermediate states in intramolecular proton transfer processes on a single molecular scale for the first time. Our results not only help people understand the proton transfer process in porphyrin phthalocyanines, It also provides a new idea and a new method to explore the molecular dynamics process on the surface by using the non-relaxation fluorescence imaging technology. In chapter 4, we extend the existing STML detection mode. First, in order to characterize the near-field optical properties of nanostructures, we developed a near-field collection model. The STM induced luminescence of GaAs (110) and H2TBPP molecules adsorbed on the surface of GaAs (110) and on the surface of GaAs (110) have been studied by using the fiber probe coated with semiconductor transparent conductive film (ITO) as the tip of the STM needle. The near field detection has been preliminarily realized. Secondly, in order to obtain the angular distribution and polarization characteristics of single molecule radiation in tunnel junctions, and to analyze the important information of molecular dipole orientation in tunnel junctions, we developed a photon collection system on the back of samples of ultra-high vacuum STML at low temperature. At present, the detection of rear focal plane imaging has been preliminarily realized, which lays a foundation for the further study of monolayer light source and optoelectronic integration.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TH742;TB383.1
【参考文献】
相关期刊论文 前1条
1 董振超;张杨;陶兴;杨金龙;侯建国;;扫描隧道显微镜诱导发光的历史和进展[J];科学通报;2009年08期
，本文编号：2207187
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/2207187.html
