Large light-induced modulation of the Metal Insulator Transition in photoconductor/Mott heterostructures*

Some Mott insulators exhibit a metal-to-insulator transition (MIT) across which the electrical resistance shows large changes. Modification of the electrical transport with an electric field has been extensively investigated and its use in emerging applications such as neuromorphic computing and voltage controlled optoelectronics seems very promising. Here we investigate the modification of the transport properties with light. We have discovered large effects using heterostructures consisting of a photoconductor CdS, film on top of ultrathin layers of the archetypal Mott insulators: VO₂ or V₂O₃. For CdS/VO₂, we observed a non-volatile light induced modulations of the MIT resulting in resistance changes of up to 3 orders of magnitude. On the other hand, for the CdS/V₂O₃ bilayer, we found a volatile light-induced modulations of the transition temperature (T_MIT) of ~140 K, with resistance changes as large as 6 orders of magnitude. We will discuss the possible physical origin of this interesting effect.