High-Performance Broadband Floating-Base Bipolar Phototransistor Based on WSe₂/BP/MoS₂Heterostructure

Recently, there are increasing interests in two-dimensional materials, as a result of their outstanding electrical and optical properties and numerous potential applications in optoelectronic devices. Here, we first report on a bipolar phototransistor based on WSe 2 -BP-MoS 2 van der Waals heterostructure, showing its broadband photoresponse from visible to the infrared spectral regions. Broadband photoresponsivities for visible (532 nm) and the infrared (1550 nm) light waves reach up to 6.32 and 1.12 A W 1–, respectively, which are both improved by tens of times in comparison with similar photodiode devices composed of WSe 2 -BP. The phototransistor also exhibits ultrasensitive shot noise limit specific detectivities which are 1.25 × 10 11 Jones for visible light at wavelength λ = 532 nm and 2.21 × 10 10 Jones for the near-infrared light at wavelength λ = 1550 nm at room temperature. It is a promising candidate for progressive development of photodetector, with implementation of smaller sensor elements, large sensing area, super-high integration, and broadband photoresponse.