Thickness and shape-controlled growth of methylammonium lead bromide single crystals for nuclear radiation detector fabrication

Space-confined inverse temperature crystallization growth was studied to grow high quality methylammonium lead bromide (MAPbBr3) single crystals with controlled shape and thicknesses, specifically for the applications in nuclear radiation detector development. By accurately controlling the heating and crystallization temperatures, molar concentrations and the space confinement methods, square-shaped single crystals with thicknesses varying from 0.5 to 2 mm were obtained. These crystals showed good crystallinity as verified by x-ray diffraction and the room temperature photoluminescence (PL) measurements. Radiation detectors were fabricated by depositing metal contacts of different types on opposite faces of the crystal. The Au/MAPbBr3/Cr detectors exhibited mostly linear current–voltage (I–V) characteristics, with no hysteresis effect. The resistivity of the crystal was high in the order of 108 Ω cm. The detector showed stable x-ray pulse response, where a minimum variation in photocurrent amplitude was observed. Furthermore, the gamma detection property of this detector was also confirmed.