In this dissertation, the signal response of the pnCCD under electron illumination was studied comprehensively. The pnCCD is a spatially resolving, fast, energy dispersive, charge-coupled-device (CCD) semiconductor detector that has great potential for applications in transmission electron microscopes (TEMs) as deduced from previous measurements with (X-ray) photons. However, there had not been an elaborate analysis of the pnCCD under electron illumination. The present work closes this gap with a detailed physical explanation and modelling of the signal response of the pnCCD to electrons established on a systematic investigation with experiments, simulations and analysis. A series of conducted, application-oriented experiments showed that the pnCCD improves analysis and methods in electron microscopy.
As part of this work, a camera with the pnCCD was developed and mounted at TEMs at numerous research institutes. In a diversity of experiments, single TEM electrons were imaged in the energy range of 20keV to 300keV . From this data, energy spectra of single electrons were determined. With the analysis of these spectra in combination with simulations, the scattering of the TEM electrons inside the detector could be explained as well as the readout signals. A relevant influence on the measured signal is exerted by the backscattered electrons that do not deposit their full energy in the detector, but rather scatter out of it. On the basis of the developed analysis, the precise number of incoming TEM electrons can now be determined.
The relationships between the readout signals, the pnCCD’s parameters and the parameters of the TEM (mainly the energy of the TEM electrons) were determined and explained. Furthermore, the spatial resolution was investigated. The spatial resolution could be increased with several models allowing images created with single TEM electrons to offer pixel sizes smaller than the given physical sizes. For TEM electron energies of