Scanning electron microscopy (SEM) is used for metrology of nanometer-scale features in semi-conductor electronics applications and for emerging nanotechnologies. SEM signals include sec-ondary- and backscattered-electron yields. They are determined by the interaction between the instrument (beam energy, beam shape, detector characteristics) and the sample (its materials, topography, …). Misinterpretation of signals results in errors that are important for nanometrology. These must be understood and corrected to obtain sufficient accuracy. We expect opportunities for postdoctoral applicants to develop SEM reference samples in NIST’s NanoFab and to develop models to simulate electron scattering, secondary electron generation, electron transport, scattering in gases (for variable pressure SEM), the effect of e-beam shape on imaging, the effects of electric fields and charging, and electron detectors.