Results on radiation hardness of black silicon induced junction photodetectors from proton and electron radiation

The stability of black silicon induced junction photodetectors under high-energy irradiation was tested with 11 MeV protons and 12 MeV electrons using fluence of 1⋅1010 protons/cm2 and dose of 67 krad(Si) for protons and electrons, respectively. The energies and dose levels were selected to test radiation levels relevant for space applications. The degradation was evaluated through dark current and external quantum efficiency changes during (within 1 h after each step) and after (some days after) full irradiation sequences. Furthermore, the black silicon photodetectors were compared to planar silicon induced junction and planar silicon pn-junction photodetectors to assess the contribution from both black silicon and semiconductor junction characteristics. The calculated radiation damage factors of all types of studied detectors were in agreement with values previously published in literature. The external quantum efficiency results demonstrated that the combination of black silicon surface and aluminum oxide induced junction provides a good radiation hardness against the used proton and electron doses showing degradation only in the near infrared region due to bulk damage. The pn-junction photodetectors with silicon dioxide passivation exhibited significant degradation also in the ultraviolet responsivity after electron irradiation.