Filament localization and tuning of resistive switching characteristics in VO_x via selective ion irradiation

Various materials exhibit resistive switching, a useful feature which lends well to the development of novel bioinspired electronic devices, notably artificial neurons and synapses for neuromorphic computing. In a number of material systems, this effect occurs through the percolation of conducting filaments across an otherwise insulating matrix. Often, the location and switching parameters of the resistive switching are impacted by inherent material defects, which poses a serious challenge for scalability of neuromorphic circuits. By selectively engineering defects using a focused ion beam, we report a novel method of locally tuning a material's electronic properties (i.e. conductivity and metal-insulator transition temperature) and by extension, controlling the location and geometry of the conducting filament. In addition to confining the conducting filament to the irradiated region, we observe a greater than 3 orders of magnitude reduction in resistive switching power. Our work demonstrates that local ion irradiation is an efficient tool for fine-tuning material properties related to resitive switching. This offers promising avenues for new energy-efficient biomimetic circuitry.