High-Performance Broadband Floating-Base Bipolar Phototransistor Based on WSe2/BP/MoS2 Heterostructure

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 WSe2-BP-MoS2 van der Waals heterostructure, showing its broadband photoresponse from visible to the infrared spectral regions. Broadband photo-responsivities for visible (532 nm) and the infrared (1550 nm) light waves reach up to 6.32 and 1.12 A W1-, respectively, which are both improved by tens of times in comparison with similar photodiode devices composed of WSe2-BP. The phototransistor also exhibits ultrasensitive shot noise limit specific detectivities which are 1.25 x 10(11) Jones for visible light at wavelength lambda = 532 nm and 2.21 x 10(10) Jones for the near-infrared light at wavelength A = 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.