Nitrogen-Doped Carbon Quantum Dots on Graphene for Field-Effect Transistor Optoelectronic Memories

The development of field-effect transistor-based (FET-based) non-volatile optoelectronic memories is vital toward innovations necessary to improve computer systems. In this work, for the first time, the unique charge-trapping and charge-retention properties of solution-processed colloidal nitrogen-doped carbon quantum dots (CQDs) are harnessed to achieve functional optoelectronic memories programmable by UV illumination with a multilevel writing possibility. Of particular note, long-lasting memory function can be achieved thanks to the vast charge trapping sites provided by the N-doped CQDs and the resultant photo-gating effect is exercised on the graphene FET. The achieved memory can be erased by a positive gate bias which provides sufficient carriers to remove trapped charges through recombination. This study highlights the possibility to engineer high-performance all-carbon non-volatile FET-based optoelectronic memories through manipulating and coupling the charge-trapping properties of colloidal CQDs and graphene.