Deep traps study of radiation-damaged semi-insulating GaAs detectors introduced by neutrons

Neutron detectors based on bulk semi-insulating (SI) GaAs represent an interesting and perspective solution due to its relatively high resistance against neutrons. Therefore SI GaAs material seems to be an excellent candidate for fabrication of a neutron imaging detector. Set of detectors based on SI GaAs material was bombarded with various integral neutron fluencies (1011–1015 n cm−2). The performance of detectors was evaluated via measured spectra of 241Am radionuclide sources. From the results a significant worsening in detection ability was observed at fluencies exceeding (over) ∼1013 n cm−2. These observations are explained by lattice defects in the base SI GaAs material or in the overall detector structure (electrode interfaces, surface) introduced by neutrons. Photo-induced current transient spectroscopy was used to determine changes in deep level states of bulk SI GaAs base material.