微结构对单根Ni/NiO核壳纳米线器件阻变性能的影响

Influence of Microstructures on the Resistive Switching Performance of the Single Ni/NiO Core-Shell Nanowire Device

通过化学还原和热处理的方法制备出了具有核壳结构的Ni/NiO纳米线,利用扫描电子显微镜、X射线衍射、热重分析等手段对不同退火温度下的样品进行了结构表征和分析,分析了样品微结构对单根Ni/NiO纳米线器件阻变性能的影响。结果表明:随着退火温度的升高,Ni/NiO纳米线表面逐渐光滑,NiO薄膜层结晶度提高,NiO平均粒径逐渐增大,氧化层也逐渐变厚。I-V测试曲线表明,在300℃退火条件下,单根Ni/NiO纳米线器件展现出优异的阻变性能,开关比大,开关阈值电压小;但随着温度的升高,单根Ni/NiO纳米线器件阻变性能明显下降,其原因可能是因为退火温度的进一步升高导致了NiO薄膜层厚度的增加并提高了薄膜的结晶质量阻碍了导电细丝在NiO层内的产生造成的,只有在适当温度处理下出现的微结构才能使Ni/NiO纳米线器件具有最优化的阻变性能。

The Ni/NiO core/shell nanowires were prepared by chemical reduction and heat treatment.The structures of Ni/NiO core-shell nanowires under the different annealing temperatures were characterized and analyzed by the scanning electron microscopy,X-ray diffraction,and thermogravimetric analyzer.The effect of the sample microstructure on the resistive switching performance of the single Ni/NiO core-shell nanowire device was analyzed.The results show that the surface of the Ni/NiO nanowire becomes smoother and the crystallinity of the NiO layer is improved with the increase of annealing temperature.Meanwhile,the average size of the NiO crystalline grain and the thickness of the NiO layer in the Ni/NiO nanowire increase.The I-V test curves show that the single Ni/NiO core-shell nanowire device annealed at 300 ℃ has a excellent resistive switching performance with high ON/OFF ratio and low switching threshold voltage.The resistive switching performance of the single Ni/NiO nanowire device obviously declines with the increase of the annealing temperature.It is possibly resulted from the thicker NiO layer and higher crystal quality of NiO,which prevent the formation of the conductive filaments in the NiO layer with the further increase of the annealing temperature.These findings suggest that an optimized resistance switching performance can be obtained when the microstructures of the Ni/NiO nanowire device are annealed at proper temperature.