The influence of interface states and bulk carrier lifetime on the minority carrier behavior in an illuminated metal/insulator/GaN structure

An influence of electronic states at an insulator/GaN interface on the behavior of excess holes in an ultraviolet-illuminated metal/ SiO2/n-GaN structure has been studied by numerical simulations for weak (gate bias of −0.1 V ) and strong (−1 V ) depletion, in a wide range of excitation light intensities (from 10101010 to 1020 photons cm−2 s−1) and for various bulk carrier lifetimes (from 11 to 100 ns). It has been found that the interface states with densities of 1012 eV −1 cm−2 dramatically reduce the total (integrated in the whole GaN layer) density of photogenerated holes and thus degrade the sensitivity of the metal/insulator/GaN-based photodetector.

► We model the hole behavior in UV illuminated metal/insulator/n-GaN structure. ► We compare the impact of the interface states and the bulk carrier lifetime. ► High state density (1012 eV −1cm−2) is detrimental for the device characteristics. ► The results are important for GaN-based ultraviolet detectors.