Photo-Electric response of 4H-SiC APDs at High-Level incident flux

•Avalanche photodiodes (APDs) are being intensively studied as a replacement for Photomultiplier tubes (PMTs) to be used in weak ultraviolet (UV) detection due to its excellent optoelectronic properties.•The paper is the first research work reported on the influence of high-level incident flux on the photo-electric response performance of 4H-SiC SPADs and found the non-linearity of single-photon-detection performance.•Our paper proposes how to improve the dynamic range of APD. Lower threshold voltage and higher bias voltage can improve the monotonic range at least up to 4 × 104 photons/s·μm2.