Preparation and modification of metal nano-contacts Photo-excitation

我们开发了新的技术，通过结合光照射和外加电场的影响来控制尺寸小于几十纳米的金属结构。金属纳米结构的一个很有前途的应用是利用表面增强拉曼散射(SERS)进行单分子检测。尽管几种复杂的方法在产生完全可重复的SERS活性方面取得了成功，但由于需要专门的合成或制备技术，制备往往很复杂。制备SERS活性底物的新的、简便、可控的技术有待开发。在这项研究中，我们的技术是控制玻璃衬底上的金属纳米结构，以制备出具有很强SERS信号的薄膜。通过控制溶液中的电化学势制备了可持续的金属纳米接触，通过电化学刻蚀或沉积的方法在溶液中可持续细金丝的间隙处制备了铜、银、镍、钯和铅的金属纳米接触。在室温下，在铜、银、镍和钯的接触处表现出相对稳定的电导量子化行为，呈现一个单位值。与其他金属相比，铅触头的电导量子化行为相当不稳定。通过控制不同溶液中的电化学电位，考察了Au纳米触头的机械稳定性。

We have developed novel techniques to control metal structures in the size range less than a few tens nm by combing the effects of photo-irradiation and applying an external electric field. One of the promising applications of metal nanostructures is for single molecular detection employing surface enhanced & Raman scattering (SERS). Although several sophisticated methods were successful with respect to generation of fully reproducible SERS activity, the preparations were often complicated due to the need for specialized synthetic or preparative techniques. Novel facile and controllable techniques to prepare SERS active substrates should be developed. In this study, our technique to control metal nanostructure on glass substrate was used to prepare the films showing very strong SERS signal. Sustainable metal nanocontacts were fabricated under controlled electrochemical potential in solution.Metal nanocontacts of Cu, Ag, Ni, Pd, and Pb were fabricated via the electrochemical etching or deposition method at a gap of sustainable thin Au wires in solution. Relatively stable behaviors of the conductance quantization exhibiting a unit value were apparent at the contacts of Cu, Ag, Ni, and Pd at room temperature. Conductance quantization behavior of the Pb contact was rather unstable in comparison with other metals. echanical stability of Au nanocontact was also examined by controlling electrochemical potential in various solution containing ClO_<4->, S0_4^<2->, Cl^-ions.