High-Temperature Flexible WSe2 Photodetectors with Ultrahigh Photoresponsivity

Industries such as aerospace or military have promoted the development of high-temperature photodetectors. However, current high-temperature photodetectors exhibit low photoresponsivity (<10 A/W) because heat resistant materials usually have poor optical sensitivity. 2D transition metal dichalcogenides demonstrate outstanding optoelectronic properties, but they cannot survive at elevated temperature. It is challenging to realize photodetector with both high-temperature-resistant capability and high photoresponsivity. Here, we report WSe2 photodetector which can endure record high temperature of 700 ℃ in air (1000 ℃ in vacuum). It is the most heat resistant 2D-material device ever reported. Graphene/h-BN heterostructure with atomically flat interface is the key for high-temperature protection. Unconventional negative photoconductivity (NPC) phenomenon appears at high temperature. Operated in NPC mode, the device exhibits photoresponsivity of 2.2×106 A/W, which is ~105-fold higher than that of state-of-the-art high-temperature photodetectors, and even higher than that of existing WSe2 photodetectors. Furthermore, current high-temperature photodetectors are rigid, which limits their applications. Our device demonstrates excellent flexibility, making it highly adaptive to various shaped surfaces. Our approach can be extended to other 2D materials and may stimulate the research of novel 2D-material devices working in harsh environment.