单晶体氧化锌微/纳米带电阻与长度的特性研究

Properties of Single Crystal Zinc Oxide Micro/nanobelt with Resistance and Length

采用化学气相沉积法制备单晶体氧化锌微/纳米带,通过银膏将其固定在镀有二氧化硅绝缘层的硅基板上,用镀有铂金属的导电原子力显微镜探针触碰单晶体氧化锌微/纳米带,构成测量回路。通过试验获得氧化锌微/纳米带电阻与其长度呈非线性关系,并且当长度到达切断长度时,微/纳米带电阻突然增大;试验测得切断长度为17.5μm,且切断长度附近的电阻与长度关系也是非线性。建立氧化锌微/纳米带的平面导电模型,说明在氧化锌微/纳米带中电子倾向于在主导电平面内运动。分析得出单晶体氧化锌微/纳米带晶格面的各向异性是使其电阻与长度呈指数的增长关系的主要原因,与试验相符。此外,通过向氧化锌内掺杂Bi_2O_3、Co_2O_3等杂质发现,杂质的加入能使氧化锌微/纳米带的电阻与长度的非线性关系发生改变。

The single crystal zinc oxide micro/nanobelt（MB/NB） is synthesized by the method of chemical vapor deposition, then it is fixed on a silicon wafer which is coated with a silicon oxide insulating layer by silver paste. The Pt coated conductive atomic force microscope（AFM） probe, which acted as one electrode, scanned the MB/NB surface, which also acted as the other electrode, in tapping mode to acquire I-V curves. The measured result reveals that the electrical resistance of the Zn O MB/NB is exponential to its length, and when the length reaches the cut off length, the resistance increases suddenly. The cut off length is 17.5 μm by the experimental measured, and the I-V curves near the cut off length are non-linear also. A planar conductive model about the flow of electrons in ZnO MB/NB are proposed, through the analysis of model draw the conclusion that the electrons tend to move within the dominant conductive plane and the anisotropic of single crystal ZnO MB/NB with lattice plane is the main reason which lead to the nonlinear relationship between resistance and length. The results fit the experimental measurement well. In addition, by doping Bi2O3 and Co2O3, the nonlinear relationship between the length and the resistance of the ZnO MB/NB may change.