Mechanisms Affecting the Anomalous Responsivity of Back‐Illuminated p–i–n AlGaN Solar‐Blind Photodetectors

A study on the bias‐dependent spectral responsivity of back‐illuminated p–i–n AlGaN UV photodetectors with different p‐AlGaN layer thicknesses is investigated. The results reveal an anomalous reduction in peak responsivity under zero bias when the p‐AlGaN layer thickness is relatively thin. Further investigations indicate that this anomaly can be attributed to the additional Schottky junction formed between the p‐AlGaN layer and metal. The quality and thickness design of the p‐AlGaN layer play a crucial role in enhancing the performance of back‐illuminated p–i–n AlGaN solar‐blind photodetectors.