Information

The Jeol ARM 200F is a world-class high-resolution (scanning) transmission electron microscope (S)TEM. The Warwick ARM 200F is aberration-corrected both in probe-forming optics (probe size FWHM <80 picometres) and in image-forming optics (image resolution <80 picometres). This allows atomic resolution imaging both in STEM and TEM modes, as shown in the examples (right).

The microscope has a Gatan Quantum electron energy loss spectrometer (EELS) to allow detection and quantification of the elemental composition down to the atomic level. Dual EELS allows both low-loss and core-loss regions of the spectrum to be collected simultaneously and a fast shutter allows data rates of up to 1000 spectra/second.

The microscope also currently has a 100mm2 Oxford Instruments windowless energy-dispersive X-ray (EDX) detector. This also yields composition maps with atomic resolution; both EDX and EELS spectra can be collected simultaneously at high data rates.

Specification

• Schottky field emission gun (FEG)
• Operation at 80 and 200 kV
• Double aberration correction (STEM and TEM)
• Electron energy loss spectroscopy (EELS)
• Windowless, large solid angle energy dispersive X-ray spectroscopy (EDX)
• STEM resolution <80 pm with BF, ADF, HAADF detectors
• Atomic resolution imaging and elemental analysis.
• STEM images 200x to 150,000,000x
• TEM images 50x to 2,000,000 x
• Specimen size 3 mm diameter
• Gatan Orius SC1000 CCD camera

Example images

Atomic resolution STEM image of MoSe2–WSe2 lateral monolayer semiconductor heterojunctions.¹

Atomic resolution TEM image using exit wave reconstruction (EWR) of graphene with overlaid ball and stick model.²

Relevant Publications

¹ C. Huang et al. Nature Materials, 2014, 13, 1096

² R.J. Kashtiban et al. Nature Comms, 2014, 5, 4902

UK-based reseachers outside Warwick can access our aberration-corrected TEM and STEM by contacting r dot beanland at warwick dot ac dot uk