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SEM

Scanning Electron Microscopy (SEM) is a technique, where a focussed beam of accelerated electrons is scanning over a sample. Electrons which are backscattered or secondar generated electrons are collected on a detector. Dependenging on the type of detector, different signals and sample characteristics can be acquired. The electron beam is steered by electromagnetic lenses.

We have three SEMs available at DTU Nanolab. Click on the instrument to find more information about the equipment and available techniques:


AFEG	QFEG	Nova

Comparison between SEMs at DTU Nanolab - building 314/307

Equipment	Nova	QFEG	AFEG	Helios
Purpose	Conductive samples in High Vac Charge reduction in Low Vac X Ray Analysis with EDS Crystallographic analysis using EBSD and both On and Off axis TKD In-situ experiments with Heating and Gas injection	Conductive samples in High Vac Charge reduction in Low Vac Environmental control using Peltier stage Cryogenic sample fixing/stabilization using cryo stage X Ray Analysis with EDS	Conductive samples in High Vac Charge reduction in Low Vac X Ray Analysis with EDS and WDS	Conductive samples in High Vac Micro and Nano milling/fabrication using various gases and FIB X Ray Analysis with EDS Crystallographic analysis using EBSD and Off Axis TKD
Equipment position	Building 314 Room 060	Building 314 Room 011	Building 314 Room 034	Building 314 Room 061
Resolution	The resolution of a SEM is strongly dependent on sample type and the operator. Resolution quoted is using sputtered gold on carbon
Resolution	High Vacuum operation in Mode II: 1.0 nm at 15 kV (TLD detector and optimum working distance) 1.8 nm at 1 kV (TLD detector and optimum working distance) Low Vacuum operation in Mode II: 1.5 nm at 10 kV (Helix detector and optimum working distance) 1.8 nm at 3 kV (Helix detector and optimum working distance)	High vacuum 0.8 nm at 30 kV (STEM) 1.0 nm at 30 kV (SE) 2.5 nm at 30 kV (BSE) - 3.0 nm at 1 kV (SE) High vacuum with beam deceleration option 3.0 nm at 1 kV (BD mode + BSE) Low vacuum - 1.4 nm at 30 kV (SE) 2.5 nm at 30 kV (BSE) 3.0 nm at 3 kV (SE) Extended vacuum mode (ESEM) 1.4 nm at 30 kV (SE)	High vacuum 0.8 nm at 30 kV (STEM) 1.0 nm at 30 kV (SE) 2.5 nm at 30 kV (BSE) - 3.0 nm at 1 kV (SE) High vacuum with beam deceleration option 3.0 nm at 1 kV (BD mode + BSE) Low vacuum - 1.4 nm at 30 kV (SE) 2.5 nm at 30 kV (BSE) 3.0 nm at 3 kV (SE)	Electron Column Operation in Mode II 0.8nm @15kV 0.9nm @1kV Ion Column 4.5nm @ 30kV
Detectors	ETD/TLD Secondary Electrons BSED Back Scatter Electrons LVD/LFD Low Vac SE Helix Low Vac SE EDS X Ray by energy EBSD Electron Back Scatter Diffraction TKD Transmission Kikuchi Diffraction STEM Scanning Transmission Electron Microscopy GAD Low Vac BSED	ETD Secondary Electrons BSED Back Scatter Electrons LVD/LFD Low Vac SE GSED ESEM SE EDS X Ray by energy STEM Scanning Transmission Electron Microscopy	ETD Secondary Electrons BSED Back Scatter Electrons LVD/LFD Low Vac SE GSED ESEM SE EDS X Ray by energy STEM Scanning Transmission Electron Microscopy	ETD/TLD Secondary Electrons ABS Annular BSED EDS X Ray by energy EBSD Electron Back Scatter Diffraction CDEM Continuos Dinode Electron Multiplier
Stage specifications	X 150mm Piezo Y 150mm Piezo Z 10mm R 360⁰ Piezo T 70⁰	X 50mm Y 50mm Z 50mm R 360⁰ T 70⁰ Manual	X 50mm Y 50mm Z 50mm R 360⁰ T 70⁰ Manual	X 150mm Piezo Y 150mm Piezo Z 10mm R 360⁰ Piezo T 70⁰
Options	B	C	D	E
Max sample size	Consult with DTU Nanolab staff as weight, dimensions, pumping capacity and technique all play a roll in the sample size

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