Transmission electron measurements cross-sectional images

The entrance optics to the analyser is usually chosen so that it can be tuned to nearly constant transmission over a large energy range. The gun optics is also usually chosen so that the beam can be focussed at the same position with the same image size over a wide energy range. This is necessary in order to avoid distortion of peak shapes and resonance features and inaccuracies in the cross-section measurements. After transmission through the analyser a simple lens transfers the electrons to the surface of an electron multiplier, usually a channeltron, which is operated in the pulse count mode. 

Cross-sectional transmission electron microscope with an FEI Tecnai G2 Sphera microscope operating at 200 kV was used to image the MQW microstructure. The as-grown samples were investigated by PL measurements. 

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