Transmission Electron Microscope
A field emission electron microscope, referred to as transmission electron microscope, is used to project an accelerated and focused electron beam onto a very thin sample. The electrons collide with the atoms in the sample to change the direction, resulting in stereo Angular scattering. The size of the scattering angle is related to the density and thickness of the sample, so the different images can be formed. Generally, the resolution of a field emission electron microscope is 0.1 to 0.2 nm, and the magnification is tens of thousands to millions of times. It is used to observe ultrastructures, that is, structures less than 0.2 microns that cannot be seen under an optical microscope.
1. Point resolution: 0.19nm;
2. Line resolution: 0.10nm;
3.Acceleration voltage: up to 200kV;
4. Magnification: 50 ~ 2M × in TEM mode; 200 ~ 150M × in STEM mode;
5. STEM resolution: ≤0.16nm;
6. Equipped with a five-axis motor to drive the automatic sample stage.
Instrument application range:
Observe the internal microstructure of various materials, the study of electron diffraction analysis and high-resolution electron microscopy, crystal structure and crystal properties, and cooperate with energy spectrometer to perform qualitative and semi-quantitative micro-analysis of various elements. The widely used in nanotechnology, materials, physics, biology, chemistry, environment, optoelectronics and other fields.
1.Block sample, the sample size must be a circle with a diameter of 3mm, and the thickness must be less than 200nm.
2 Powder and liquid samples, it is required that the sample can be evenly dispersed on the support film and dried.
3 Ion thinning requires the sample to be less than 30um, not more than 50um to punch into Ф3mm; magnetic samples cannot be thinned.
4 Biological samples can be directly fixed with glutaraldehyde.
5 Because TEM-EDS is a thin sample test, unlike SEM-EDS, due to the limitations of the instrument itself, samples that meet the following requirements can be considered for testing TEM-mapping:
(1) Because TEM samples must be prepared on a copper mesh covered with carbon film, samples containing C and Cu elements cannot be tested for mapping;
(2) Because Cu element is unavoidable and the content is very high, the content of the element that is required to be tested is generally greater than 5% before attempting mapping;
(3) Since element N is an element with a small atomic number, it is difficult to detect in TEM. Generally, the content of element N is more than 10%.