This book focuses on two aspects of deep-level traps in semiconductor devices: on one hand the platinum impurities are studied as example of defects diffused purposefully in pin power ultra-fast diodes in order to increase their recovery performance; on the other hand, the ionizing radiation-induced defects are considered. In this case, some academic samples are studied before and after irradiation with a 3 MeV proton beam. The devices are studied by means of IV, CV, CVT and DLTS techniques. This study deals with the characterization and dynamics of the defects, starting from the realization ab initio of new defects-spectroscopy setups. It is a research performed within the "IAEA Coordinated Project on Utilization of Ion Accelerators for Studying and Modelling Ion Induced Radiation Defects in Semiconductors and Insulators" (2012-2015).