On the UV responsivity of neutron irradiated 4H-SiC

We report on UV responsivity of 4H-SiC photodiodes irradiated by 1 MeV neutrons.Current-voltage characteristics, photoresponse spectra, and responsivity were obtained with lightwavelength from 200 to 450 nm. Photoresponse results slightly affected by irradiation up to thethreshold fluence critical=81014 cm−2. At fluences critical the rejection rate is in the order of103 in the range of 200–320 nm while it is less than 102 at about 320 nm. The abrupt increase inmidgap traps induced by irradiation at critical, observed by photoinduced current transientspectroscopy, proves carrier generation/trapping to be the controlling mechanism for theresponsivity. © 2008 American Institute of Physics.