2D WSe2/MoS2 van der Waals heterojunction photodiode for visible-near infrared broadband detection

Two dimensional (2D) layered van der Waals (vdW) atomic crystals are an important class of emerging materials due to their unique physical properties. In particular, the nature of dangling–bond–free surfaces in 2D vdW materials enables the formation of heterojunctions without the constraint of atomic lattice match. Here, we report on a 2D WSe2/MoS2 multilayer van der Waals heterojunction PN diode and its application for visible-near infrared broadband detection. The WSe2/MoS2 PN diode shows excellent performance with an ideality factor of 1.5 and a high rectification (ON/OFF) ratio of over 106. This PN diode exhibits spectral photo-responses from the ultraviolet (405 nm) region to the near infrared (808 nm) region with obvious photovoltaic behaviors (very clear open circuit voltage and short circuit current). In addition to the static behavior, photocurrent switching behaviors are clearly observed under periodic illuminations at up to 1 KHz. The device shows a linear response within the optical power density range of 10−5 W cm−2 to 1 W cm−2 and a linear dynamic range is estimated to be 123 dB.