Tip locking mechanism for STM light Emission Spectroscopy

用于 STM 发射光谱的尖端锁定机构

• 批准号: 07554050
• 负责人: UEHARA Yoichi
• 金额: $ 0.32万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07554050/
• 关键词: STM; Spectroscopy; High spatial resolution measurement; surface science; 光放出; STM発光分光; 発光

STM ligth emission spectroscopy is a powerful tool for investigating properties of surface microstructures. Since the beam diameter of electrons from the STM tip is narrower than -1 nm, one can expect to obtain the light emission spectra of individual nanometer-scale structures.One obstruction to STM light emission spectroscopy with the expected spatial resolution is unintended change of tip position due to ambient temperature fluctuation etc. (tip drift) during spectral measurement. Since STM light emission intensity is weak long exposure time (a few hundred seconds or longer) is required. As result spatial resolution of STM light emission spectroscopy becomes worse than the expected value (the beam diameter).In this project a new tip position locking mechanism for STM light emission spectroscopy has been developed. The way of the locking is as follows : Let us assume that the total exposure time required to observe emission spectra is nxT (n times T). First topographic image of an area on the sample surface is taken. Then STM light emission spectrum from a microstructure in the area is measured for the time period of T (the exposure time of the spectrum is T). Again topographic image of the area same as that taken before the spectral measurement is observed and the amount of the drift during the exposure is calculated by comparing the two STM images. Then the tip is moved back on the microstructure and the next spectrum is measured. By repeating the above procedure n times and accumulating the spectra STM light emission spectrum corresponding to the exposure time of nxT can be measured with the spatial resolution better than the amount of drift during the time period T.If T is selected enough small STM light emission spectroscopy with high spatial resolution becomes possible.

STM LIGTH发射光谱是研究表面微结构性质的有力工具。由于从STM针尖发出的电子束直径小于-1 nm，可以获得单个纳米结构的光发射光谱。在光谱测量过程中，由于环境温度波动等原因，针尖位置的意外变化(尖端漂移)是阻碍STM光发射光谱达到预期空间分辨率的一个障碍。由于STM发光强度较弱，需要长时间曝光(几百秒或更长时间)。因此，STM光发射光谱的空间分辨率变得比预期值(光束直径)差。在本项目中，我们开发了一种新的STM光发射光谱尖端位置锁定机构。锁定的方式如下：让我们假设观察发射光谱所需的总曝光时间为NxT(n乘T)。首先拍摄样品表面上的区域的地形图像。然后测量该区域内微结构的STM光发射光谱的时间T(光谱的曝光时间为T)。同样，观察与光谱测量之前相同的区域的地形图像，并通过比较两个STM图像来计算曝光期间的漂移量。然后将尖端移回微结构上，并测量下一个光谱。通过重复上述过程n次并累积光谱，可以以比时间段T内的漂移量更好的空间分辨率来测量与NXT的曝光时间相对应的STM光发射光谱。如果选择足够的T，则可能实现高空间分辨率的小STM光发射光谱。