High-performance self-powered photodetector with broadened spectrum absorption based on black phosphorus/Cs2SnI4 heterostructure

Self-powered photodetectors have huge potential applications in wearable electronics, extreme environments and military fields. In this work, two types of van der Waals Cs-I-BP and Sn-I-BP heterostructures have been studied fully through first-principles calculations. The results demonstrate that both Cs-I-BP and Sn-I-BP heter-ostructures have type-II band alignment. The EP values of Cs-I-BP and Sn-I-BP heterostructures reach separately 6.02 eV and 5.64 eV by calculating across the interface. As a result, the two types of heterostructures form a large built-in electric field and possess a good self-powered capability. The absorption coefficients of the Cs-I-BP and the Sn-I-BP heterostructures significantly enhance in the ultraviolet and infrared regions. Moreover, under the modulation of biaxial stress, the heterostructure can be changed from a semiconductor to a conductor, and the energy band alignment type is changed from type II to type I as well as the light trapping ability in the near -infrared region is significantly enhanced. These findings suggest that the Cs-I-BP and the Sn-I-BP hetero-structures have promising application for tunable high performance optoelectronic devices.