Semi-insulating InP detectors with guard ring electrode

Particle detectors made with a guard-ring electrode (GR) on a semi-insulating Ti and Zn co-doped InP crystal grown by Czochralski technique are reported. Cathode electrode consisted of an active circular electrode and an encircling GR. Detection performance of particle detectors was measured by pulse-height spectra with alpha particles emitted from the ²⁴¹Am source. An improved energy resolution of the detector with the GR compared to detectors without GR was observed. Applied bias voltage on the GR reduced the leakage current of the detector and improved spectral characteristics at room temperature (RT). The best values of charge collection efficiency 99 % and of energy resolution 0.9 % at 230 K or respectively 17 % and 16 % at RT for the detector with the GR is presented. These results deserve further investigation of InP co-doped with Ti and Zn as suitable material for X- and gamma-ray detectors operating at RT.