Dependence of dark current and photoresponse on polarization charges for AlGaN‐based heterojunction p–i–n photodetectors

The influence of the polarization charges on the properties of AlGaN‐based heterojunction p–i–n ultraviolet photodetectors was investigated. It is found that the polarization charges at the hetero‐interface can enhance the electric field intensity and result in an increased dark current. On the contrary, the polarization charges can lower the photoresponse because the direction of polarization electric field is opposite to the applied electric field in the light absorption layer.