Influences of polarization effect and p-region doping concentration on the photocurrent response of solar-blind p–i–n avalanche photodiodes

The influences of polarization and p-region doping concentration on the photocurrent response of Al_0.4Ga_0.6N/Al_0.4Ga_0.6N/Al_0.65Ga_0.35N p–i–n avalanche photodetector are studied in a wide range of reverse bias voltages. The simulation results indicate that the photocurrent under high inverse bias voltage decreases with the increase of polarization effect, but increases rapidly with the increase of effective doping concentration in p-type region. These phenomena are analyzed based on the calculations of the intensity and distribution of the electric field. A high p-region doping concentration in the p–i–n avalanche photodetector is shown to be important for the efficient compensation for the detrimental polarization-induced electrostatic field.