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近十年来,光电子显微技术取得了长足进步并已商业化。光电子显微是一种高衬度的成像技术,对材料表面电子结构高度敏感。本文介绍光电子显微镜的成像原理,并着重分析其衬度机制。简要总结光电子显微术在表面结构分析,表面化学,磁学,以及半导体器件表征等方面的应用。目前光电子显微术的两个重要发展方向是利用同步辐射光源和脉冲激光光源做激发源;利用脉冲激光的多光子激发光电子显微术可以对较高功函数(大于光子能量)的材料成像;而脉冲时间分辨光电子显微术可用来研究表面瞬态电子的弛豫动力学机制。文章介绍了在实现飞秒时间分辨以及多光子激发的光电子显微方面的进展。我们利用多光子光电显微术对溅射制备的纳米结构银薄膜表面进行成像,结果表明多光子成像照片上存在一些高强度的亮点,而在单光子成像照片未观察到类似现象。推测这些亮点源于纳米结构银表面的等离子激元的高局域选择性激发。文章还介绍了利用光电子显微术原位观察CuZnAl形状记忆合金的热诱导相变。
In the past ten years, photoelectron microscopy has made great strides and has been commercialized. Photoelectron microscopy is a high contrast imaging technique that is highly sensitive to the electronic structure of the material surface. This article introduces the principle of the photo-electron microscope imaging and focuses on the contrast mechanism. Briefly summarize the application of photoelectron microscopy in surface structure analysis, surface chemistry, magnetism, and semiconductor device characterization. At present, two important developmental directions of photoelectron microscopy are the use of synchrotron radiation sources and pulsed laser sources as excitation sources; pulsed laser multiphoton excitation photoelectron microscopy can image materials of higher work function (photon energies) Pulsed time-resolved photo-electron microscopy can be used to study the relaxation kinetics of surface transient electrons. The paper presents the progress of optoelectronics in achieving femtosecond temporal resolution and multiphoton excitation. We used multi-photon photomicroscopy to image the surface of sputtered nanostructured silver thin films. The results show that there are some high intensity bright spots on multiphoton photomicrographs, but no similar phenomenon is observed on single photon photomicrographs. It is speculated that these bright spots originate from the high localized selective excitation of plasmons on the surface of nanostructured silver. The article also introduced the use of photoelectron microscopy in situ observation of CuZnAl shape memory alloy heat induced phase transition.