Coincidence electron microscopy studies on coherent and incoherent cathodoluminescence using Timepix3

Abstract

When electrons interact with a material, they can induce the emission of light—a phenomenon known as cathodoluminescence (CL). This emitted light may originate either directly from the electron impact or through intermediate processes, classified as coherent or incoherent CL. A primary distinction between these mechanisms lies in the temporal delay between the electron-matter interaction and subsequent photon emission. Additionally, the underlying excitation processes may be distinguished by detecting electron-photon coincidences using advanced time-resolved sensor technology, such as detectors capable of registering single-particle events with nanosecond precision. In this Master's thesis, a coincidence measurement setup using a Timepix3 camera and single-photon counting modules is presented in a transmission electron microscope (TEM). A statistical evaluation method for analyzing time differences between electron-photon pairs is introduced to reveal and interpret temporal correlations. Finally, the experimental setup is tested on a silicon membrane and a micro diamond containing silicon vacancy centres to study electron-photon correlations in coherent and incoherent cathodoluminescence.