【作者】 胡阳；

【导师】 李震；

【作者基本信息】 华中科技大学 ， 软件工程， 2020， 硕士

【摘要】 随着相变存储器的尺寸微缩,相变材料纳米线的研究颇具价值。纳米线不仅可以作为测试系统来研究维度和尺寸对材料物理性质的影响,还是新型纳米器件的组成部件。本文主要针对电化学法制备的Bi₂Te₃纳米线进行自组装方法和电学性能研究。主要论述了以下内容:首先利用MATLAB软件针对Bi₂Te₃纳米团簇进行了数学建模分析。在金属半导体接触的基础上建立M-S-M模型,对实验所得的Ⅰ-Ⅴ曲线提取出了 Bi₂Te₃纳米团簇的输运参数,例如电导率,载流子浓度和迁移率。通过MATLAB仿真不同肖特基势垒高度和不同金属半导体接触面积对纳米器件Ⅰ-Ⅴ特性曲线的影响,得到肖特基势垒高度是影响Ⅰ-Ⅴ曲线对称性的主要因素这一结论。使用COMSOL软件对不同形状组装电极的电场和介电电泳力进行了仿真,相对于三角形和矩形而言圆形电极的介电电泳力稳定区域宽度较为适中更利于组装纳米线,得到了圆形电极是最佳的介电电泳组装电极的结论。将介电电泳应用于Bi₂Te₃纳米线的组装上,用较为便捷的方式得到了适合该材料的介电电泳组装参数。先用仿真的方法得到了介电电泳频率对Bi₂Te₃纳米线组装的影响。再根据组装实验快速得出了一个较为适中的组装电压,最后通过电极组实验讨论时间参数对组装效果的影响。发现装配参数（1V,500KHZ,60s）可以产生了较高比例的单根Bi₂Te₃纳米线。针对介电电泳组装成的单根Bi₂Te₃纳米线进行电学测试,得到良好的可重复相变特性。在相同条件下组装得到单根Bi₂Te₃纳米线晶态电阻值为750K欧姆,双根纳米线器件晶态阻值为300K欧姆,阻值约为两倍证明测试结果可信,组装效果良好。更多还原

【Abstract】 As the size of phase change memories shrinks,the study of phase change material nanowires is of great value.Nanowires can not only be used as a test system to study the effects of dimensions and sizes on the physical properties of materials,but also as a component of new nanodevices.This thesis focuses on the self-assembly method and electrical properties of Bi₂Te₃ nanowires prepared by electrochemical methods.It mainly discusses the following:（1）Mathematical modeling and analysis of Bi₂Te₃ nanoclusters were first performed using MATLAB software.Based on the metal-semiconductor contact,an M-S-M model was established,and the transport parameters of Bi₂Te₃ nanoclusters were extracted from the experimental Ⅰ-Ⅴ curves,such as conductivity,carrier concentration,and mobility.（2）The effects of different Schottky barrier heights and different metal-semiconductor contact areas on the Ⅰ-Ⅴ characteristic curve of nano-devices are simulated by MATLAB,and the conclusion that the Schottky barrier height is the main factor affecting the symmetry of the Ⅰ-Ⅴ curve is obtained.（3）The COMSOL software was used to simulate the electric field and the dielectrophoretic force of assembled electrodes of different shapes.Compared to triangles and rectangles,the width of the stable region of the dielectrophoretic force of the circular electrodes is moderate and more favorable for the assembly of nano wires.The circular electrode is the conclusion that the best electrode for dielectrophoresis assembly.（4）Dielectrophoresis was applied to the assembly of Bi₂Te₃ nanowires,and the dielectric electrophoresis assembly parameters suitable for the material were obtained in a more convenient way.Firstly,the influence of the frequency of dielectric electrophoresis on the assembly of Bi₂Te₃ nanowires was obtained by simulation.According to the assembly experiment,a relatively moderate assembly voltage was quickly obtained.Finally,the effect of time parameters on the assembly effect was discussed through electrode group experiments.It was found that assembly parameters（1V,500KHZ,60s）can produce a single Bi₂Te₃ nanowire with a higher proportion.（5）Electrical tests on a single Bi₂Te₃ nanowire assembled by dielectric electrophoresis have obtained good repeatable phase change characteristics.Under the same conditions,the resistance value of a single Bi₂Te₃ nanowire in the crystalline state is 750KQ which is about twice that of the two nanowires.It proves that the test results are credible and the assembly is stable.更多还原