High-performance metal electrode-enhanced double parallel p-n heterojunctions photodetector

Highly sensitive uncooled mid-wave infrared (MWIR) photodetectors have a very wide range of applications ranging from the sensor and image to communications. Traditional MWIR detection semiconductors require liquid nitrogen cooling to depress dark current, which impeded the wide applications of devices. Here, we report a metal electrode-enhanced double parallel BP/InSe/BP van der Waals heterostructure uncooled MWIR photodetector. The device exhibits ultrahigh light on/off ratio of 10(8) and a very low dark current of 0.16 pA. The competitive performance includes high photoresponsivity (R) of 27.8 A W-1, excellent specific detectivity (D*) of 3.8 x 10(12) cm Hz(1/2) W-1, very low noise equivalent power (NEP) of 3.7 x 10(-16) W Hz(-1/2), and fast response speed of tau(r) = 3.5 mu s and tau(d) = 2.4 mu s in the visible range. Notably, in the MWIR range, the light on/off ratio of similar to 10(4), NEP of 3.0 x 10(-13) W Hz(-1/2), and D* of 4.8 x 10(9) cm Hz(1/2) W-1 was realized. The work sheds light on developing a high-performance uncooled MWIR photodetector by designed band alignment.