Anisotropic Optoelectronic Properties of Melt-Grown Bulk CsPbBr Single Crystal.

All-inorganic perovskite CsPbBr has been considered as one of the star semiconductors due to its inspiring optoelectronic properties and higher stability than the organic-inorganic hybrid counterparts. The preparation of large-size single crystals with low trap density and the performance optimization on the devices still challenge the commercial application of this material. Here the large transparent CsPbBr single crystal (ϕ 24 mm × 90 mm) was grown by a modified Bridgman method. With the determination of crystallographic directions, the anisotropic optoelectronic properties were investigated for the first time. The result shows a high electron mobility (11.61 cm/(V s)) along the b axis, one order of magnitude higher than that along the c axis. Moreover, the photoresponse measurement yields a high responsivity (5.83 A/W) and external quantum efficiency (1360%) on the (001) plane irradiated by the 532 nm laser diode with 1 mW/cm under 10 V bias, which is a 305% enhancement compared with the (010) plane. Our study on anisotropic optoelectronic properties of CsPbBr will provide a significant approach to enhance the performance of single-crystalline devices.