Abstract: In electron grating diffraction, the peak width in the diffraction pattern is a direct measure of the free electron transverse coherence length. A broadened peak indicates decoherence of the free electron wavepacket. Using the above band-gap photoexcitation, we created a charge pattern on a GaAs surface that interacts with the diffracted electron matter wave through a dipole field. We observed a significant broadening of the diffraction peak as electrons flew over certain regions of the charge structure. The decoherence strength can be controlled through the excitation laser that is applied to the GaAs plate. As only one electron is present in the chamber at any time, such a system is suitable for studying decoherence of single electrons. In this talk, I will present some recent experimental results and discuss a possible decoherence model.