Growth and Characterization of Inorganic Perovskite Crystals for Gamma Detectors

Development of room-temperature gamma detectors is important for nuclear physics applications. State-of-the-art detectors such as CZT exhibit electric defects that can derail photo-generated carrier hopping leading to degraded detector performance. Inorganic perovskites such as CsPbBr₃ (CPB) are promising detector materials due to a large gap between valence and conduction bands. The absence of Van der Waals gaps enables good electrical and mechanical properties of CPB - high mobility lifetime product (10⁻² 𝑐𝑚² 𝑉⁻¹), low defect density - and long-term stability for detecting gamma rays and charged particles. In this work, crystals of CPB were grown from their own melt in vacuum sealed quartz ampoules by Bridgman method using a three-zone vertical furnace; CPB crystallization was achieved using 0.06 K min^-1 cooling gradient with the 18 K cm^-1 temperature gradient. The CPB ingots were sectioned to wafers and characterized using x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDS), scanning electron microscope (SEM), and photoluminescence (PL) technqiues. The PL analysis shows that the synthesized CPB crystals have a band gap of 2.3 eV. This wide band gap perovskite is promising material for the development of large-volume gamma detectors.