We investigate defects in 4H-SiC p-n junction diodes introduced trough nanoindentation procedure. A nanoindentation load range between 3 mN and 15 mN was explored. Scanning Electron Microscopy and Transmission Electron Microscopy analysis are adopted for the morphological and crystallographic investigation of defects; electrical characterisations of junction diodes are performed to investigate the conduction mechanism, both at RT and versus measurement temperature. Electrical parameters such ideality factor, leakage current and series resistance, are extracted for the processed diodes and compared to virgin one. Activation energy of about 1.7 eV and 0.2 eV are extracted for defects in virgin and in mechanically processed devices, respectively. Electro-optical characterisation is performed adopting Emission Microscopy measurements evidencing a diffuse photons emission in the visible range …