Self-powered broadband photodetectors based on Bi2O2Se with asymmetric contact areas

Abstract

Self-powered broadband photodetectors are widely used in military reconnaissance, outdoor environmental sensing, wearable medical monitoring. Current commercial broadband photodetectors based on conventional materials are structurally complex, high cost, and external power consumption. 2D materials emerge as promising candidates for the development of novel photodetectors with superior performances. The construction of self-powered photodetectors predominantly employs the heterostructures or metal–semiconductor–metal (MSM) configurations, which still suffer from either multiple steps of material growth, transferring, alignment or various photolithography, film deposition techniques. Herein, a simple and effective asymmetric contact strategy is proposed to fabricate Bi2O2Se-based self-powered broadband photodetectors with asymmetric Au contact areas. The photodetector exhibits excellent performance under 350–1150 nm illumination. The responsivity is as high as 1.38, 4.76, and 0.63 A/W under 350, 550, and 1050 nm, respectively, which are much higher than those of the previously reported self-powered photodetectors based on Bi2O2Se nanosheets. Meanwhile, the self-powered photodetector has a high external quantum efficiency of 1073.16 % at 550 nm. In addition, the photodetector has excellent stability in the air and enables both imaging and optical communication. Owing to the simple architecture, cost-effectiveness, straightforward manufacturing process, and impressive performance, the proposed self-powered photodetectors hold considerable promise for future applications.