Matching Terahertz and Hall Mobilities as a Hallmark of Intrinsic Charge Transport in Metal-Halide Perovskites

Abstract

Charge-carrier transport in soft-lattice materials, including metal-halide perovskites, is often perceived to be highly heterogeneous across different length scales, and influenced by both the intrinsic (dynamic) thermal electronic disorder and extrinsic (static) disorder due to crystal defects, impurities, grain boundaries, and surface states. As a consequence, the reported carrier mobilities obtained by different electrical and optical measurement techniques frequently disagree, raising a critical question: can a truly intrinsic charge transport regime (that is, a regime not dominated by static disorder) extend across macroscopic single crystals of these materials? Here, we demonstrate such a regime in an exemplary metal-halide perovskite system, epitaxial CsPbBr$_{3}$ single crystals, where the local mobility obtained via optical pump-terahertz probe (OPTP) spectroscopy quantitatively agrees with the macroscopic transport mobility across a broad range of experimental conditions. Using a dedicated device platform that enables concurrent Hall-effect and OPTP measurements on the same single-crystalline sample, we obtain consistent room-temperature mobilities of ~ 30 cm$^{2}$V$^{-1}$s$^{-1}$, among the highest reliably reported for CsPbBr$_{3}$. Both techniques reveal band-like temperature dependence of the hole mobility with similar power exponents, confirming that the same intrinsic transport mechanism governs the ultrafast/local and steady-state/macroscopic responses. These results show that defect-free charge transport is achievable in soft-lattice perovskites on millimetre length scales and establish a robust methodology for benchmarking intrinsic mobility in emerging semiconductors.