In this study, we used n+ p mesa diodes where the highly arsenic doped n+ top layer was grown by molecular-beam epitaxy on top of a 5-μm thick p-type layer grown by chemical-vapour deposition. The diodes were irradiated with 2MeV electrons at room temperature and the resulting defects in the p-type region were studied by Laplace and standard deep-level transient spectroscopy. A new defect with an apparent energy position of 0.20 eV above the valence band is shown to migrate from the n+ top layer into the p-type material where it is …