Interplay between Photoinduced Charge Injection and Material Defects in VO_x/CdS Mott/Photoconducting Heterostructures

The Metal-Insulator Transition (MIT) exhibited by a number of transition metal oxides has garnered much interest for various technological applications, including hardware-level implementation of neuromorphic computing architectures, as it can induce several orders of magnitude change in a material's resistivity. Various electronic degrees of freedom can influence this transition, including the presence of defects and doping. In our study, we couple two forms of doping: selectively engineered defects via ion irradiation and photoinduced carrier injection, to tune and suppress the MIT. We fabricated ion-irradiated VOx thin film devices with a layer of an archetypal photoconductor, Cadmium Sulfide, to study the interplay between photodoping and material defects. We show that ion irradiation is a controllable mode of selectively engineering defects within vanadium oxides and can be used for tuning transport properties, resistive switching, and the MIT in VOx/CdS heterostructures. We further analyze the influence material defects have on altering the photosensitivity and dynamic response of optoelectronic Mott/Hybrid heterostructures.