Theoretical study on interfacial impact ionization in AlN/GaN periodically stacked structure

Abstract

A theoretical study on interfacial ionization in the AlN/GaN periodically stacked structure (PSS) avalanche photodiode (APD) has been carried out to explain why the experimental electron ionization coefficient is higher than that in the simulation result. Full band structures for GaN and AlN are combined at the heterojunction interface of the PSS APD for the calculation of the suitable initial ionization state in AlN. Many suitable initial states exist in the γ valley of AlN, where scattering rates are restricted and ultimately result in a higher ionization coefficient.