Cover story: Jia LM, Cheng L, Zheng W. 8-nm narrowband photodetection in diamonds. Opto-Electron Sci 2, 230010 (2023).

Spectrally-selective photodetection plays a crucial role in various applications, including target imaging and environmental monitoring. Traditional deep-ultraviolet (DUV) narrowband photodetection systems consist of broadband photodetectors and filters, which complicate the architecture and constrain imaging quality. This cover paper demonstrates an electronic-grade diamond-based DUV narrowband photodetector with a peak external quantum efficiency (EQE) of 228 nm and a spectral response with the full width at half maximum (FWHM) of less than 8 nm. By examining diamond photodetectors with varying dislocation densities, it is proposed that mitigating the defect-induced trapping effect to achieve charge collection narrowing, assisted by free exciton radiative recombination, is an effective strategy for narrowband photodetection. The as-prepared narrowband photodetector exhibits extremely-low dark current due to low defect density, resulting in a high specific detectivity (~10¹³ Jones) and a compliant linear dynamic range (LDR~118 dB). With germicidal UV light sources as an example, the spectrally-resolved imaging capability of this photodetector is presented. These findings underscore the promising potential applications of electronic-grade diamond in narrowband photodetection and offer a valuable technique for identifying electronic-grade diamond.