Research Progress in the Metal Oxide Heterojunction Photodetectors

Metal oxides (MOs) have been widely used in photodetection because of advantages such as easy preparation, high stability, and selective transport of carriers. The MO materials exhibit strong light absorption properties. However, there are issues with MO photodetectors such as their low response speed and large dark current owing to the surface effects and defect states. The built-in electric field in the heterojunction can effectively promote the separation of photogenerated electron-hole pairs, thus improving the device response speed and reducing the dark current. Thus, the construction of metal oxide heterojunction photodetectors (HPDs) is of great significance for the further application of MO in the field of optoelectronics. This paper introduces the interface properties of MO and elaborates on the working mechanism of metal oxide HPDs around the PN, PIN, and isotype heterojunctions. Next, the performance parameters of MO/MO and MO/Si HPDs with different structure and response in UV-Vis-NIR band are analyzed and compared. Subsequently, improved methods of the metal oxide HPDs performances are discussed. Finally, the development of metal oxide HPDs is discussed.