Uncovering the modest hole mobility for the intrinsic single crystal CsPbBr3 by variable-temperature time of flight measurement

Abstract

CsPbBr3 single crystal is a promising candidate for room temperature radiation detector. However, the experimental mobilities reported exhibit considerable discrepancy, ranging widely from 10 to 4500 cm2/(V · s) at room temperature. Here, vertical Bridgman grown CsPbBr3 single crystal has been used to measure the mobility accurately using pulse-biased time-of-flight method. The hole mobility for CsPbBr3 at room temperature is modest to be around 25 cm2/(V · s). The value of the corresponding power-law index n for hole mobility on temperature (μ ∼ T-n) is around −1.23 in the range of 155–350 K, which is well consistent with the previous FET and Hall effect measurements, as well as theoretical calculations. The polar optical phonon rather than acoustic phonon is confirmed to be responsible for scattering carriers at room temperature. Our study gives solid evidence on the modest mobility in the intrinsic (not dominated by defects) CsPbBr3 semiconductor, which may limit the application of CsPbBr3 in high flux photon counting detectors.