Estudo e aplicação de nanofios de SnO₂ para o desenvolvimento de memórias resistivas

Abstract

SnO₂ semiconductor nanowires are promising systems for the study of memristive phenomena due to their high surface-to-volume ratio and the presence of intrinsic defects that strongly influence their electrical transport properties. In this work, tin dioxide nanowires were synthesized using the Vapor–Liquid–Solid (VLS) method and characterized by X-ray diffraction and scanning electron microscopy, confirming the formation of crystalline nanostructures. Based on these nanostructures, devices with two distinct geometries - a single nanowire and a nanowire network - were fabricated under different levels of environmental isolation. Electrical characterization was carried out by means of current–voltage (I–V) measurements using voltammetric cycles with different experimental parameters, as well as voltage pulse measurements. The results show that the single-nanowire devices exhibit essentially ohmic behavior, whereas the nanowire network devices display nonlinear current–voltage characteristics and hysteresis. Furthermore, the electrical response of the nanowire networks was found to depend on parameters such as measurement geometry, time interval, voltage step, maximum applied voltage, and electrical excitation history. In particular, an evolution of the electrical response over successive measurement cycles and changes in the electrical state following the application of voltage pulses were observed. These results indicate that the observed behavior emerges from the nanowire network structure and its interfaces, and is consistent with characteristics associated with memristive devices.