Universitiy of Potsdam

Applied Condensed Matter Physics

Prof. Dr. Reimund Gerhard
2016-11-04 16:30 by Manuel Schulze

Typical oscilloscope traces

Uniform bulk-charge distributions are easily detected as linearly increasing or decreasing electric fields, and single charge layers should lead to square-wave-like response signals. The following animated GIF seqences show the propagation of the pressure step and the corresponding oscilloscope reading.

single charge layer
single layer

uniform bulk charge
bulk layer

The PPS experiment can be calibrated if the particle velocity in the sample is calculated from the acoustic transmission ratio between quartz and sample material, where the particle velocity in the quartz depends on its properties and on the amplitude of the voltage step.

Thus, from the oscilloscope traces (voltage vs. time), the film-depth and electric-displacement axes can be calculated for all PPS responses.