【作者】 张丹；

【导师】 肖宗源； 洪文晶； 张静怡；

【作者基本信息】 厦门大学 ， 化学工程， 2018， 硕士

【摘要】 目前硅基器件小型化即将达到其性能极限,为实现分子器件替代硅基器件,研究单分子尺度电输运行为十分必要。快速发展的机械可控裂结技术(Mechanically Controllable Break Junction,MCBJ)为研究单分子尺度的电输运性质创造了条件。本论文利用MCBJ技术展开了以下两个工作,主要研究内容及成果如下:1.杂原子掺杂对量子干涉效应的调控研究在纳米尺度的分子器件电输运性质不再遵循欧姆定律,电子输运过程中能级或传输途径不同的电子量子波函数的干涉现象不容忽视。为进一步完善单分子尺度量子干涉效应理论,本课题将N原子引入已知具有量子干涉的寡聚苯乙炔(Oligophenylene Ethynylene,OPE)体系,基于MCBJ分子电导测试及密度泛函理论(Density functional theory,DFT)计算的结果表明,通过引入杂原子获得空间分离的电导通路,实现相消量子干涉调控。2.碳基分子器件的构筑及电输运研究碳基分子器件被认为是取代硅基电子器件的可能选择,因此对全碳电子学的研究十分有必要。在裂结技术中常常使用金属电极捕捉目标分子构筑分子器件,但金属电极往往带有原子易迁移、可功能化范围较窄等缺点。本课题采用石墨烯电极替代金属电极,利用π-π作用构筑一系列石墨烯/富勒烯/石墨烯分子结,首次将全碳电子学的研究推进到数埃尺度。研究发现不同大小及共辄性的富勒烯可以通过不同的带隙来调控电输运性能,此外,可通过氮原子的掺杂引入共振来调控分子结的电输运性质,同时这些结论被DFT计算证实。这项工作也预示着富勒烯在分子电子设备中具有极大的应用前景。更多还原

【Abstract】 The miniaturization of silicon-based devices is approaching the physical limits.To explore the potential of molecular devices for electronics appplications,it is necessary to investigate the charge transport of electronic devices at the single-molecule scale.In this thesis,we have carried out two experimental studies using MCBJ technology and the results are as follows:1.Gating quantum interference effects by heteroatom dopingSince the charge transport of single-molecular devices no longer obeys Ohm’s law,quantum interference effects cannot be ignored.We introduce the N atom into quantum interference OPE molecular system.The result of breaking junction experiments and DFT theoretical calculations indicate that the introduction of heteroatom can bring spatially separated conductance pathways to gate destructive quantum interference.2.The fabrication and charge transport investigations of carbon based molecular devicesCarbon based molecular devices are considered to be alternatives to silicon based electronic devices,it is very important to investgate the all-carbon electronics.Metal electrodes are often used to capture target molecules and construct molecular devices in breaking junctions,which have the disadvantages of atoms easily migration and narrower functional ranges.We use grapheme electrodes instead of metal electrodes and build a series of graphene/single-fullerene/graphene junctions by π-π stacking.For the first time,the all-carbon electronics research has been developed to angstroms scale.It is found that different sizes and conjugative fullerenes can tune electrical transport through the junction by bringing band gaps engineering.More interestingly,our work demonstrate that the doped heteroatom could introduce new resonance to tune the charge transport of the molecular junctions.These conclusions are confirmed by DFT calculation.This work indicate that the fullerene has the promising application for molecular electronics devices.更多还原