Temperature dependence of electron and hole signals in irradiated p +-n-n+ diodes in the presence of continuous carrier injection

The temperature dependence of electron and hole signals in irradiated p⁺-n-n⁺ diodes was studied in the presence of carrier injection. Diodes fabricated on high-resistivity (15 kΩcm) silicon wafers were irradiated with neutrons up to a 1 MeV-neutron equivalent fluence of 2 × 10¹⁴ /cm² . The detector signal after illumination with a fast (full-width at half-maximum ~ 1 ns) red (λ = 670 nm) light pulse was amplified with a fast amplifier (f_t = 1 GHz) and recorded with a fast digitizing oscilloscope. During measurements, the electron or hole densities were changed by illuminating the detector with light of short penetration depth. The effect of charge trapping was studied by observing the change in effective space-charge density as the flux of injected carriers was varied. The effect of continuous carrier injection on signal decay at cryogenic temperatures was also observed