Ultraviolet Photodetectors Based on 4H‐SiC With Honeycomb‐Like Light‐Trapping Structures

ABSTRACT Silicon carbide (SiC), as a wide‐bandgap semiconductor, exhibits significant potential for visual‐blind ultraviolet (UV) detection due to its excellent material properties. To further improve the performance of SiC UV detectors, we introduce the honeycomb‐like light‐trapping microstructures at the surface of SiC, which are fabricated by using a facile and efficient photoelectrochemical (PEC) etching method. The mechanism underlying the formation of the light‐trapping microstructures is carefully investigated. It is found that the anisotropic etching is dependent on the crystal orientation of SiC. After the formation of the honeycomb‐like light‐trapping microstructures, optical characterizations reveal substantial suppression of UV reflection and enhanced absorption due to the increased light path and multiple internal reflections. The self‐powered SiC UV photodetector with the light‐trapping microstructures shows a peak responsivity of 0.187 A/W at the wavelength of 290 nm, which corresponds to an external quantum efficiency of 80%. This self‐powered photodetector also demonstrates excellent performance in imaging and optical communication. The low‐cost, scalable, and selective etching for the formation of the light‐trapping microstructures has important implications for the development of high‐performance SiC‐based optoelectronic devices.