机械可控纳米劈裂法实现单分子电导值的测量

Utilization of Mechanically Controllable Break Junction for Single Molecule Conductance Measurement

为了获得电子在单分子结中传输的特性,研制了具有高稳定性的机械可控纳米劈裂装置芯片.利用此芯片及相应机械装置,获得了能在皮米级精度上操纵间距的纳米电极对;并实现了稳定的单个金属离子所桥接的分子结(电极-分子-金属离子-分子-电极).在保持配合物不变的前提下,置换不同金属离子,测量了其所桥接的单分子结的电导值,发现Ca2+络合物的电导值>>Zn2+络合物的电导值>Ni2+络合物的电导值.结合密度泛函理论的计算,验证了所得实验装置的可靠性及实验结果的正确性.

In order to investigate the electrical properties of electron transport through the single mole- cule, a chip for the mechanically controllable break junction （MCBJ） was fabricated. With such a chip and corresponding mechanical setup, a pair of nanoelectrodes can be obtained and the distance between the electrodes can be adjusted with pieometer accuracy. The molecular junctions bridged by metal ion （ electrode-molecule-metal ion-molecule-electrode junctions） were established using the technology of me- chanically controllable break junction. The corresponding current-voltage characterization was studied. Furthermore, the influence of different metal ions on complexes conductivity was investigated, while leav- ing the ligands mainly unchanged. The conductance of the junctions depends strongly on the kind of bridged metal ion, and the order is Ca2＋ junction 〉〉 Zn2＋ junction 〉 Ni2＋ junction. Supported by the density functional theory calculation, the reliability of our device and the accuracy of the data were veri- fied.