Fully optical switching memory based on an oxidized GQD–FeOx heterojunction with 106 negative photoconductance ratio

A fully optical control device can provide positive photoconductance memory (PPM) and negative photoconductance memory (NPM), enabling the device to execute fully optical computing. However, the NPM triggering involves complex modulation and small ratio. Here, we propose an oxidized GQD–FeOx heterojunction optoelectronic memory that integrates the PPM and NPM effects into the same cell, thus building all-in-one fully optical computing. The PPM originates from the electrons that are generated from neutral Vo sites under low resistance state while the NPM effect with an ultrahigh ratio of 106 is contributed by the increase in neutral Vo under high resistance state. The theory calculation illustrates that the NPM effect heavily relies on the geometric confinement and partial reflections of the oxidized GQDs and the localization effect of the FeOx. This work provides a significant structure design and photogenerated electron dynamic for the development of fully optical computing.