Polycrystalline β -Ga 2 O 3 Used in Neuromorphic Information Storage: Trapping Centers for Carriers Leads to Persistent Photoconductive Effect

Neuromorphic visual sensors (NVSs) address the bottleneck of traditional devices with synaptic behaviors that help solve the challenges of large power consumption and slow processing speeds. The carrier trapping layer plays an important role in the synaptic behavior of NVSs. In this work, we propose a polycrystalline$\beta $-Ga2O3as both photosensitive and carrier trapping material to simplify the multilayer structure of NVSs. The persistent photoconductivity (PPC) effect of polycrystalline$\beta $-Ga2O3photosensor has been enhanced by utilizing grain boundaries. The trapping effect is thoroughly investigated by characterization and electrical tests. Furthermore, it is demonstrated that the$\beta $-Ga2O3device can mimic biological neuromorphic behavior with a variety of basic synaptic behaviors. Finally, the device has been proven to be able to store optical images for more than 520 s and ASCII messages for more than 300 s. It broadens the road for the development of Ga2O3in neuromorphic memory devices.