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利用水热法制备了NiO纳米粒子,基于GaIn/NiO/ITO器件结构,研究了焙烧温度对NiO纳米粒子薄膜阻变特性的影响。XRD分析发现,随焙烧温度由400至900℃,NiO纳米粒子结晶性提高,逐渐显立方相,粒子分散性变好。电学测试表明,NiO纳米粒子薄膜具有可重复双极阻变特性,开电压约-1.3 V较稳定。随焙烧温度提高,器件开关比由1407急剧降至11左右,原因是纳米粒子结晶后,其晶界势垒减小,载流子迁移率增大,致开关性变差。伏安特性曲线分析发现,纳米粒子薄膜低阻态荷电输运为欧姆特性,高阻态符合肖特基发射,判断阻变机理为阈值电场及焦耳热导致的氧空位细丝的形成与断裂。
NiO nanoparticles were prepared by hydrothermal method. Based on the structure of GaIn / NiO / ITO devices, the influence of calcination temperature on the resistive properties of NiO nanoparticles was investigated. XRD analysis showed that with the calcination temperature from 400 to 900 ℃, the crystallinity of NiO nanoparticles increased, and the phase of cubic phase became obvious. The dispersion of particles became better. Electrical tests show that the NiO nanoparticle films have repeatable bipolar resistance change characteristics, and the turn-on voltage is about -1.3 V more stable. With the increase of the calcination temperature, the switching ratio of the device drops sharply from 1407 to about 11, because the barrier of the grain boundary decreases and the carrier mobility increases when the nanoparticles are crystallized, resulting in poor switching performance. Voltammetric characteristic curve analysis showed that the charge transport of low resistivity nano-film was ohmic and the high resistivity was in accordance with Schottky emission. The resistance change mechanism was judged as threshold electric field and the formation and fracture of oxygen vacancies caused by Joule heating .