Imaging built-in electric fields and light matter by Fourier-precession TEM

Lorenzen, Tizian; März, Benjamin; Xue, Tianhao; Beyer, Andreas; Volz, Kerstin; Bein, Thomas; Müller-Caspary, Knut (2024): Imaging built-in electric fields and light matter by Fourier-precession TEM. Scientific Reports, 14 (1). ISSN 2045-2322

Abstract

We report the precise measurement of electric fields in nanostructures, and high-contrast imaging of soft matter at ultralow electron doses by transmission electron microscopy (TEM). In particular, a versatile method based on the theorem of reciprocity is introduced to enable differential phase contrast imaging and ptychography in conventional, plane-wave illumination TEM. This is realised by a series of TEM images acquired under different tilts, thereby introducing the sampling rate in reciprocal space as a tuneable parameter, in contrast to momentum-resolved scanning techniques. First, the electric field of a p–n junction in GaAs is imaged. Second, low-dose, in-focus ptychographic and DPC characterisation of Kagome pores in weakly scattering covalent organic frameworks is demonstrated by using a precessing electron beam in combination with a direct electron detector. The approach offers utmost flexibility to record relevant spatial frequencies selectively, while acquisition times and dose requirements are significantly reduced compared to the 4D-STEM counterpart.

• Doc-Type: Article (LMU)
• Organisational unit (Faculties): 18 Chemistry and Pharmacy > Department of Chemistry
• DFG subject classification of scientific disciplines: Natural sciences
• DFG: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - 491502892
• DFG: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - 390776260