High-performance dual-mode ultra-thin broadband CdS/CIGS heterojunction photodetector on steel.

An ultra-thin CdS/CIGS heterojunction photodiode fabricated on steel firstly exhibits dual-mode broadband photodetection from ultraviolet to near infrared spectrum. In the photovoltaic mode, the CIGS photodiode, working as a self-driven photodetector, shows an outstanding photodetection capability (under a light power density of 20 µW cm at 680 nm), reaching a record detectivity of ∼4.4×10 Jones, a low noise equivalent power (NEP) of 0.