Speaker
Description
Over recent years, perovskite semiconductors have gained interest as radiation detection, one of which is formamidinium lead bromide single crystals (FAPbBr3 SCs). FAPbBr3 has been shown to be one of the more promising candidates to act as a radiation detector, however it faces many challenges during the growth and polishing processes that effect the bulk and surface properties. Recent studies have shown that issues FAPbBr3 SCs face such as lifetime, uniformity, dark currents and ion migration are caused by strain in the bulk and nonuniformity of the surface of the crystal, leading to the viability of FAPbBr3 to fail to contend with commercially used photodetectors, especially when detecting gamma radiation. Therefore, this work aims to focus on looking into the bulk and surface properties of the SCs by optimizing the growth process of FAPbBr3 SCs through the temperature ramps used during the inverse temperature crystallization (ITC) growth process. This could serve as a means of addressing the bulk issues, while surface issues are to be investigated by looking into the polishing processes. The optimizations were checked by use of digital microscopy to check the surface uniformity and the transparency, and cross polar microscopy was used to check the bulk strain distribution within the crystals. Then once the crystals showed promise, they were fitted with asymmetrical contacts (Bi/FAPbBr3/Au) in a device, and the dark currents were tested using polar biased voltage responses, continuous voltage responses and X-ray scans to see the effects of ion migration within the crystals. These optimizations and verification tests would lead to higher quality single crystals and thus better detector properties.