Microscopy and Microanalysis

Techniques and Equipment Development

Improving Fabrication and Application of Zach Phase Plates for Phase-Contrast Transmission Electron Microscopy

Simon Hettlera1 c1, Björn Gamma1, Manuel Driesa1, Nicole Frindta2, Rasmus R. Schrödera2 and Dagmar Gerthsena1

a1 Laboratorium für Elektronenmikroskopie, Karlsruher Institut für Technologie (KIT), 76128 Karlsruhe, Germany

a2 CellNetworks, BioQuant, Universität Heidelberg, 69120 Heidelberg, Germany

Abstract

Zach phase plates (PPs) are promising devices to enhance phase contrast in transmission electron microscopy. The Zach PP shifts the phase of the zero-order beam by a strongly localized inhomogeneous electrostatic potential in the back focal plane of the objective lens. We present substantial improvements of the Zach PP, which overcome previous limitations. The implementation of a microstructured heating device significantly reduces contamination and charging of the PP structure and extends its lifetime. An improved production process allows fabricating PPs with reduced dimensions resulting in lower cut-on frequencies as revealed by simulations of the electrostatic potential. Phase contrast with inversion of PbSe nanoparticles is demonstrated in a standard transmission electron microscope with LaB6 cathode by applying different voltages.

(Received March 07 2012)

(Accepted May 30 2012)

Key words

  • phase plate;
  • transmission electron microscopy;
  • phase contrast;
  • weak-phase object;
  • heating device;
  • charging;
  • contamination

Correspondence:

c1 Corresponding author. E-mail: simon.hettler@kit.edu