This project focuses on the implementation of an electrical detection scheme to investigate defect centers on single crystal surfaces under well defined under ultrahigh vacuum (UHV) conditions. The properties of surface and interfacial defects are intimately correlated with the performance of semiconductor devices. However, due to a lack of in-situ analytics with sufficient sensitivity the impact of these modifications on the surface defects become very difficult to assess. To this end, we will implement an in-situ EDMR experiment to an UHV-apparatus to investigate defects on semiconductor surfaces starting with defects low index silicon surfaces and their reactivity with gases such as hydrogen and oxygen. In a second step this strategy will be expanded to electrically active defects at the surface of SiC.