// Scanning Electron Microscopy

Scanning electron microscopes (SEM) are excellent tools for examining a wide range of material properties at the microscopic level, all the way down to structures measuring just a few nanometers. A Zeiss Crossbeam 550 provides high-resolution images at ZSW. This instrument has a field emission cathode that enables imaging of the surface morphology in the micro- to nanometer range. Less conductive samples are difficult to capture in images, but the Crossbeam’s excellent electron optics accomplish this even at low acceleration voltages. It also features a FIB (Focused Ion Beam) unit that can serve to ablate the sample in a targeted manner using a focused Ga ion beam and to deposit specific materials – typically Pt or C. Several possibilities for detecting images are available. An EDX (energy dispersive x-ray microanalysis) system from Oxford Instruments analyzes the characteristic x-rays excited by the electron beam to enable a clear determination of chemical components. This detector obtains high-resolution images of a sample’s elemental composition. Another special feature of the system is the integrated cryogenic stage, which allows the sample to be cooled down to -160°C with nitrogen to prevent the electron or ion beam from affecting the sample.