Dresden 2011 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 1: Dielectric and ferroelectric thin films 1
DF 1.3: Talk
Monday, March 14, 2011, 11:20–11:40, MÜL Elch
Low voltage ferroelectric electron emission from Pb(Zr0.4Ti0.6) thin films — •Jana Becherer1, Oliver Mieth1, Vinay Shankar Vidyarthi2, Gerald Gerlach2, and Lukas M. Eng1 — 1Institut für Angewandte Photophysik, Technische Universität Dresden, D-01062 Dresden — 2Institut für Festkörperelektronik, Technische Universität Dresden, D-01062 Dresden
We report on the electron emission from 600 nm thin ferroelectric Pb(Zr0.4Ti0.6) films. Based on a monolayer of polystyrene beads, structured top electrodes were prepared on the PZT films revealing nanometer-sized and regularly arranged apertures. The application of an ac voltage between top and bottom electrode initiates electron emission from the apertures. The emission current is measured under UHV conditions using a single electron detector for small signals and an amperemeter for larger currents.
The onset of the electron emission process could be accomplished at voltage values as low as 10 V. Emission current densities up to 3*10−8 Acm−2 for excitation voltages of 60 V were achieved.
Using Piezoresponse Force Microscopy (PFM), the polarization state within the apertures was imaged for different voltages applied between top and bottom electrode. An increasing fraction of the free surface area was found to exhibit the reversed polarization orientation for rising voltage amplitudes. Thus, it is shown that the emission process in thin PZT films is strongly correlated to the switching of the ferroelectric polarization.