A highly sensitive filterless narrowband 4H-SiC photodetector employing a charge narrowing strategy

Abstract

Silicon carbide (SiC) semiconductors with a wide bandgap have attracted much attention because they can endure harsh environments and high temperatures. SiC photodetectors based on conventional principles usually detect ultraviolet (UV) light without the ability to discriminate wavelength. Here, using the charge narrowing collection principle, we realize a highly sensitive filterless narrowband 4H-SiC photodetector. The 4H-SiC layer is sufficiently thick to facilitate charge collection narrowing of the device’s external quantum efficiency spectrum, inducing a full width at half-maximum of 14.5 nm at the peak wavelength of 355 nm. Thanks to the Fermi level pinning effect, the proposed photodetector can fully eliminate the injection current; thus it works as a photovoltaic type device with a remarkably low dark current. Consequently, the device has a photo-to-dark current ratio as high as 4 × 107, superior to the performance of most reported 4H-SiC UV photodetectors. In addition, the device can detect light signals with a power density as low as 96.8 pW cm−2, more than two orders of magnitude superior to that of the commercial product based on the photodiode principle. Moreover, it can endure high temperatures of 350 °C, demonstrating bright prospects in harsh industrial conditions.