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 light wavelength from 200 to 450 nm. Photoresponse results slightly affected by irradiation up to the threshold fluence [uppercase_phi_synonym]critical=8×1014 cm-2. At fluences ≥[uppercase_phi_synonym]critical the rejection rate is in the order of 103 in the range of 200–320 nm while it is less than 102 at about 320 nm. The abrupt increase in midgap traps induced by irradiation at [uppercase_phi_synonym]critical, observed by photoinduced current transient spectroscopy, proves carrier generation/trapping to be the controlling mechanism for the responsivity. [ABSTRACT FROM AUTHOR]