CsPbBr3 perovskite single crystals for X- and γ-radiation detectors

Methods were developed for the synthesis and growth of the inorganic perovskite CsPbBr3, which can be used for detection of optical, x-ray, and γ-radiation. The growth of single crystals of these compounds was carried out by the Bridgman method in quartz ampoules using zone-refined starting materials. The electro-physical properties of the lead cesium tribromide CsPbBr3 were studied. Two types of structures with a Cr/CsPbBr3/Ni rectifying barrier and Ni/CsPbBr3/Ni ohmic contacts were created. The resistivity of the semiconductor material (ρ≈7×109 Ohm•cm) and the activation energy of the dark conductivity (▵E≈0.8 eV) were determined. From the measurements of the optical transmission spectra, the energy gap of CsPbBr3 at 300 K was found to be Еg = 2.27 eV. The temperature dependence of the forbidden gap (Eg(T) = 2.4 - 4*10-4 T, eV) was also determined. A significant increase in photosensitivity for the Cr/CsPbBr3/Ni structure was observed at elevated temperatures. The Cr/CsPbBr3/Ni structures were shown to be sensitive to γ radiation. The FWHM of the energy resolution for an 241Am source was measured to be 15.8 keV.