Persistent Photoconductivity of Metal Oxide Semiconductors

Photonic devices, in comparison to their conventional electronic counterparts, are gaining prominence as essential constituents of an increasing array of devices and applications. This is primarily attributed to their adjustable electronic characteristics, multifunctionality, and lower energy consumption. Particularly, persistent photoconductivity (PPC), characterized by the sustained presence of photoexcitation effects beyond the immediate termination of incident light, has garnered considerable attention within the realm of photonic devices. Because comprehending and modulating the electronic attributes of semiconductors hold paramount importance for their practical applications, in this Review, we place special emphasis on elucidating the PPC effects exhibited by various metal oxide semiconductors (MOSs) and their underlying mechanisms of origin. Furthermore, it is noteworthy that, for a substantial duration, investigations on PPC were primarily confined to the theoretical domain, with neglect of its practical applications, due to its detrimental impact on the sensitivity of photodetectors. However, in recent years, researchers have embarked on exploring an array of potential applications associated with PPC, encompassing areas such as optoelectronic synapses, optical memory, and charge storage. So, we summarize the diverse applications of MOSs in the context of PPC, offering insights into the prospects for advancing research on the PPC effects of MOSs.