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Titel:Quantitative Characterization of Nanometer-Scale Electric Fields via Momentum-Resolved STEM
Autor:Beyer, Andreas
Weitere Verfasser:Munde, Manveer Singh; Firoozabadi, Saleh; Heimes, Damien; Grieb, Tim; Rosenauer, Andreas; Müller-Caspary, Knut; Volz, Kerstin
URN: urn:nbn:de:hebis:04-es2021-00265
DDC:530 Physik


4DSTEM, electric field measurements, p−n junctions, transmission electron microscopy, momentum-resolved STEM

Most of today’s electronic devices, like solar cells and batteries, are based on nanometer-scale built-in electric fields. Accordingly, characterization of fields at such small scales has become an important task in the optimization of these devices. In this study, with GaAs-based p−n junctions as the example, key characteristics such as doping concentrations, polarity, and the depletion width are derived quantitatively using four-dimensional scanning transmission electron microscopy (4DSTEM). The built-in electric fields are determined by the shift they introduce to the center-of-mass of electron diffraction patterns at subnanometer spatial resolution. The method is applied successfully to characterize two p−n junctions with different doping concentrations. This highlights the potential of this method to directly visualize intentional or unintentional nanoscale electric fields in real-life devices, e.g., batteries, transistors, and solar cells.

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