| Summary: | In this letter, novel heterostructure p-i-n GaN avalanche photodiodes (APDs) with p-type In<sub>0.05</sub>Ga<sub>0.95</sub>N layer are proposed and analyzed through Silvaco Atlas simulations. The introduction of the In<sub>0.05</sub>Ga<sub>0.95</sub>N layer generates a negative polarization charge at the p-In<sub>0.05</sub>Ga<sub>0.95</sub>N/i-GaN heterojunction interface via the piezoelectric polarization effect. Three times higher hole concentration in the p-In<sub>0.05</sub>Ga<sub>0.95</sub>N layer is obtained due to the smaller activation energy of the Mg dopant. Induced polarization charge and increased hole concentration work together to reduce the voltage drop in the p-In<sub>0.05</sub>Ga<sub>0.95</sub>N layer and enhance the electric field intensity in the i-GaN layer. The calculated results show that the heterostructure APD demonstrates a reduced operating voltage of more than 26 V and an improved multiplication gain by an order of magnitude in comparison to the conventional one.
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