Black phosphorus carbide infrared phototransistor with wide spectrum sensing for IoT applications

We demonstrate a novel black phosphorus carbide (b-PC) phototransistor with a wide absorption spectrum that spans most molecular fingerprints till 8,000 nm and a tunable responsivity and response time at an excitation wavelength of 2,004 nm. The b-PC phototransistor achieves a high responsivity (R) of 2,163 A/W and a short response time of 5.6 ps, which renders it suitable for high speed and weak signal sensing. Its noise-equivalent-power NEPshot ∼ 1.3 fW/Hz1/2 indicates infrared radiation in the femto-watt range can be detected above the shot noise level of this phototransistor. Under the same excitation power, its responsivity and detectivity performance in ambient and room temperature conditions are currently ahead of all recent top performing photodetectors based on 2D materials, showing promise for future internet-of-things (IoT) applications.