Modification of characteristics of AlGaN photodiodes by 1.6 MeV proton irradiation

Abstract

The wide direct-bandgap AlGaN is one of the most promising materials for fabrication of radiation hard, double response particle detectors for future collider facilities. However, formation of defects is unavoidable during growth and fabrication of AlGaN based devices. Furthermore, radiation defects are formed in detector structures during operation at extreme conditions. In this work, the study of electrical and optical characteristics after 1.6 MeV proton irradiation has been performed. Commercial photodiodes of GaN and AlGaN (with various Al concentrations) fabricated using epi-layers grown by metalorganic chemical vapor deposition technique on sapphire substrate have been examined. Electrical characteristics of the devices have been examined by combining pulsed technique of barrier evaluation by linearly increasing voltage, steady-state photo-ionization and deep level transient spectroscopy.