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

In many applications, the highest and lowest detectable flux are both important for single photon avalanche photodiodes (APDs). The photocurrent and single-photon-counting performance of 4H-SiC APDs are investigated under a wide-range incident flux. Experimental results show that the photocurrent is sub-linearly with the incident photon rate at high-level incident flux. In addition, the ratio of photon count rate to dark count rate is non-monotonic when the incident flux increases. The highest detectable flux of the 4H-SiC APD can be extended from 3 x 103 photons/s & BULL;& mu;m2 to more than 4 x 104 photons/s & BULL;& mu;m2 by reducing the threshold voltage and increasing the reverse voltage.

Automated summary

The photocurrent and single-photon-counting performance of 4H-SiC APDs under a wide-range incident flux were investigated. Experimental results showed that the photocurrent was sub-linear with the incident photon rate at high-level incident flux. Furthermore, the ratio of photon count rate to dark count rate was non-monotonic as the incident flux increased. The highest detectable flux of the 4H-SiC APD could be extended by reducing the threshold voltage and increasing the reverse voltage, reaching more than 4 x 104 photons/s · μm2.