The Jeol ARM200F.

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.

Specifications and Capabilities

Schottky field emission gun (FEG) Operation at 80 and 200 kV Double aberration correction (STEM and TEM) Electron energy loss spectroscopy (EELS) 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

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Relevant Publications

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

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

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