Charge Transport in Surface-Guided CsPbBr₃ Nanowires

Although metal halide perovskites (MHPs) have emerged as exceptional materials for optoelectronics, their charge transport properties remain under scientific debate. One of the reasons for this is that most charge transport measurements are conducted on polycrystalline thin films, which adds complexity to the system and makes it difficult to interpret the results in an unambiguous way. In this work, we concentrated on surface-guided planar nanowires of CsPbBr₃, single crystals with a 1D nature, which serve as a simplified model system for charge transport measurements. The surface-guided growth of MHP nanowires on sapphire results in ordered and well-defined arrays, which can be easily integrated into functional devices. We studied the charge transport in these arrays as well as in individual CsPbBr₃ nanowires, all having uniform crystallographic orientation and well-defined facets. We fabricated the first field-effect transistor on a single nanowire of MHPs and measured charge transport characteristics such as field-effect mobility and charge carrier concentration. We also observed intriguing time-dependent electrical behavior in dark and under illumination, related to the dynamic nature of these soft semiconductors. Surface-guided growth of MHP nanowires enables fast, simple and efficient fabrication of multiple devices in parallel manner for fundamental research and optoelectronic applications.