Methods for testing Zernike phase plates and a report on silicon-based phase plates with reduced charging and
Michael Marko1, Xing Meng, Chyongere Hsieh
1New York State Department of Health, Wadsworth Center, Empire State Plaza, Albany, NY 12201, USA; College of Nanoscale Science and Engineering of the University at Albany, 251 Fuller Rd., Albany, NY 12203, USA.
Abstract:
Imaging with Zernike phase plates is increasingly being used in cryo-TEM tomography and cryo-EM single-particle applications. However, rapid ageing of the phase plates, together with the cost and effort in producing them, present serious obstacles to widespread adoption. We are experimenting with phase plates based on silicon chips that have thin windows; such phase plates could be mass-produced and made available at moderate cost. The windows are coated with conductive layers to reduce charging, and this considerably extends the useful life of the phase plates compared to traditional pure-carbon phase plates. However, a compromise must be reached between robustness and transmission through the phase-plate film. Details are given on testing phase-plate performance by means of imaging an amorphous thin film and evaluating the power spectra of the images.
