Secondary electron induced current in scanning transmission electron microscopy: an alternative way to visualize the morphology of nanoparticles

Electron tomography (ET) is a powerfultool to determine the three-dimensional(3D) structure of nanomaterials in a transmission electron microscope.However, the acquisition of a conventional tilt series for ET is atime-consuming process and can therefore not provide 3D structuralinformation in a time-efficient manner. Here, we propose surface-sensitivesecondary electron (SE) imaging as an alternative to ET for the investigationof the morphology of nanomaterials. We use the SE electron beam inducedcurrent (SEEBIC) technique that maps the electrical current arisingfrom holes generated by the emission of SEs from the sample. SEEBICimaging can provide valuable information on the sample morphologywith high spatial resolution and significantly shorter throughputtimes compared with ET. In addition, we discuss the contrast formationmechanisms that aid in the interpretation of SEEBIC data.