Synthesis and Real Structure Group

High Resolution Transmission Electron Microscopy (HRTEM)

High Resolution Transmission Electron Microscopy (HRTEM)

High Resolution Transmission Electron Microscopy is an imaging mode which allows creating an image with a resolution of 0.1 nm. This is done by using phase contrast instead of analysing the intensity difference caused by absorption of the sample which is used in bright field imaging. HRTEM is widely used to analyse nanoscale properties of crystalline material such as semiconductors and metals.  

Phase contrast analyses the phase shift of the electron waves. The phase shift appears while an electron wave interacts with the positive core of an atom. The positive potential of the cores of an atomic column causes a pendulum motion of the electron. The outcome is a phase shift of the electron wave.

The exiting electron wave is a superposition of electron waves which interacted with the sample. At the imaging plane the electron waves interfere and a characteristic picture can be seen.

In fact it is necessary to know that the pictures recorded with HRTEM are no direct image of an atom. For example a high intensity does not necessarily need to be an atom column but could be.

 


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