A novel model of photo-carrier screening effect on the GaN-based p-i-n ultraviolet detector

The photo-carrier density in the depletion region of the GaN-based p-i-n ultraviolet (UV) detector is calculated by solving the photo-carrier continuity equation, and the photo-carrier screening electric field is calculated according to Poisson’s equation. Using the numerical calculation method, a novel model of photo-carrier screening effect is presented. Then the influence of photo-carrier screening effect on the distribution of photo-carrier density in the depletion region of p-i-n detector is discussed. The influence of incident power, bias voltage and carrier life time on the photo-carrier screening effect is also analyzed. It is concluded that the influence of photo-carrier screening effect on the performance of GaN-based p-i-n UV detector is non-monotone, the maximum of carrier drift velocity and the minimum of response time can be realized by adjusting the applied voltage. Besides, the incident light duration has strong impact on the photo-carrier screening effect.