An advanced self-powered visible-light photodetector based on the asymmetric Au/CsPbBr3/SmB6 junction

Abstract

CsPbBr₃ is a typical all-inorganic perovskite that has strong visible-light absorption, large carrier mobility, and long carrier diffusion length, and it has the potential for application in visible-light detection. Many attempts have been devoted to fabricating CsPbBr₃ photodetectors but the reported CsPbBr₃ photodetectors were found to have a higher dark current (∼10⁻⁹ A) and low responsivity, which remains a challenging issue for all the researchers until now. Herein, we report the development of an ambient-pressure chemical vapor deposition (APCVD) method for fabricating single-crystalline CsPbBr₃ microsheets. Based on the energy-band theory, we have devised a novel asymmetric device structure using metallic SmB₆ nanobelts and Au film as the electrodes of CsPbBr₃ microsheets to form Schottky contacts. The results show that the asymmetric Au/CsPbBr₃/SmB₆ photodetector exhibited much better photosensitive performance than the pristine CsPbBr₃ photodetector. The zero-biased Au/CsPbBr₃/SmB₆ asymmetric photodetector exhibited a large external quantum efficiency (EQE) of 44.5%, a high detectivity up to 3.38 × 10¹⁰ jones, and a large responsivity (0.184 A W⁻¹), thus surpassing many other two-dimensional (2D) photodetectors with good photoresponse behaviors. The excellent visible-light detection performance of the asymmetric photodetector can be attributed to the high separation efficiency of the photogenerated electron–hole pairs at the built-in field of the interface. Our research paves a new pathway for fabricating advanced self-powered photodetector devices based on 2D materials.