纳米分辨Aloof STEM-EELS无损研究H/D同位素材料振动谱

Damage-free measurements of vibrational modes on H/D isotopes via STEM-EELS

本文使用亚10 meV能量分辨率和纳米空间分辨的扫描透射电子显微镜电子能量损失谱技术(STEM-EELS),在aloof条件下无损测量了磷酸二氢钾(KH2PO4)和磷酸二氘钾(KD2PO4)的振动模式,并结合红外和拉曼光谱方法对测得的模式进行了标定。在此基础上,进一步定量测量了振动信号在真空中的强度衰减行为,与理论相符合。该工作对电镜下使用快电子能量损失谱研究同位素以及电子束敏感材料的空间分辨振动谱具有启发意义。

In this paper,the vibrational modes of potassium dihydrogen phosphate(KH2PO4)and potassium deuterium phosphate(KD2PO4)were damage-freely measured under the aloof condition by using electron energy loss spectroscopy in a scanning transmission electron microscope(STEM-EELS),with the nanoscale spatial resolution and the energy resolution of sub-10 meV.The measured modes were also identified using infrared and Raman spectroscopy.We further quantitatively measured the intensity attenuation behavior of the vibration signals in vacuum,which is in accordance with the theory.This work will provide critical insight for using swift electrons to study the spatial resolved vibrational spectrum of isotopes and beam-sensitive materials under electron microscope.