Electrically active defects in neutron-irradiated HPSI 4H-SiC X-ray detectors investigated by ZB-TSC technique

P. Vigneshwara Raja, N. V.L.Narasimha Murty*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Electrically active defects in high-purity semi-insulating (HPSI) 4H-silicon carbide (4H-SiC) X-ray detectors have been characterized before and after neutron irradiation by zero-bias thermally stimulated current (ZB-TSC) and high-temperature resistivity measurements. The ZB-TSC measurements prior to irradiation reveal nine hole traps in the energy range of 0.22-1.16 eV and two electron traps at Ec-0.35 eV and Ec-0.44 eV. For the same case, high-temperature resistivity measurements yield thermal activation energy in the range of 1-1.3 eV. It is considered that the hole traps at Ev+ 0.83 eV and Ev+ 1.16 eV along with defects located near the activation energies are possibly responsible for the substrate compensation. A poor resolution of 11.8-keV full-width at half-maximum (at 40 keV of 152Eu) with un-irradiated HPSI 4H-SiC detectors is attributed to the charge trapping and polarization effects. After neutron irradiation at the fluence of 10^{11} n/cm2, seven new traps ( Ev+ 0.68 eV, Ev + 1.08 eV, Ev + 1.22 eV, Ec-0.72 eV, Ec- 0.9 eV, Ec- 1.04 eV, and Ec- 1.1 eV) are identified with no significant changes in the activation energies. This indicates that the substrate resistivity is unaffected by the neutron-irradiation-induced defects. No considerable changes in the X-ray spectral response are noted at 1011} n/cm2.

Original languageEnglish
Article number7959206
Pages (from-to)2377-2385
Number of pages9
JournalIEEE Transactions on Nuclear Science
Issue number8
StatePublished - Aug 2017
Externally publishedYes


  • Defects
  • X-ray detector
  • high-purity semi-insulating (HPSI) 4H-silicon carbide (4H-SiC)
  • radiation damage
  • thermally stimulated current (TSC)


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