本研究利用循環伏安法(CV)和掃描式電子穿隧顯微鏡(STM)探討羧基硫醇分子(3- Mercaptopropionic acid，MPA )於金(100)電極上的吸附及其對銅沉積的影響，在硫酸與硫酸銅的溶液中以 5 mV/s 掃描速率所得的 CV 結果，顯示在0.3 ~ 0.6 V(對標準氫電極)電位區間(低電位電鍍銅)並無任何銅沈積的特徵峰，要到 0.03 V 時，才有明顯的銅沈積的電流，其積分電荷量也大約 372 15 μC / cm2，大致上為快一層的積分電荷量；STM 顯示在 MPA 修飾的金(100)電極上，銅優先沈積於凸起金島狀物的周邊缺陷，經過一段時間後銅原子會完整覆蓋金電極的表面，並能讓銅以層狀的方式沈積，如電位控制在銅離子的平衡電位更正時，的確沒有大量的銅沈積現象，這些結果與 CV 的結果符合，吸附的 MPA 分子的確會抑制銅在金(100)的沈積。當厚度低於十一層時，銅膜有平坦的表面形貌且形成整齊的方形平台結構，高解像掃描顯示一 c ( 2 × 2 )的整齊結構，這可能是吸附在電鍍銅上的硫酸氫根，同時也觀察到有更高的亮點，散亂地位於吸附硫酸離子之上，推測這些是 MPA分子。同時，為了解分子結構對銅電鍍的影響， 在相同實驗條件下也獲得( Mercaptoacetic acid，MAA )的結果，與 MPA 結果相比，此分子對銅沉積量影響不明顯，但為有利於低電位銅的沈積，而抑制厚層銅沈積的效果，銅沈積的薄膜形貌及分子的吸附結構和 MPA 的結果類似。當銅膜成長到達十一層時，其形貌明顯由平坦的轉變為起伏的條狀結構，此一現象可能和銅膜內銅原子的堆疊結構有關。;In situ scanning tunneling microscopy (STM) and cyclic voltammetry (CV) have been used to investigate the adsorption of thiol molecules ( Mercaptopropionic acid, MPA and Mercaptoacetic acid, MAA) and their effects on the electrodeposition of copper onto Au(100). CVs obtained with MPA-modified Au(100) electrode in sulfuric acid reveals no reductive feature between 0.3 ~ 0.6 V (vs. reversible hydrogen electrode), where Cu underpotential deposition usually commences. MPA modifier also causes delay in the bulk deposition of Cu, which results in a small reduction peak at 0.03 V. This peak contains about 372 15 μC/cm2, which correspond to the value needed to yield a full monolayer of Cu adatoms. In situ STM imaging reveals Cu nucleates preferentially at the lower edges of gold islands on MPA-modified Au(100) electrode. The deposition of Cu proceeds in a layer-by-layer (VW-mode) mode. Bulk Cu deposition does not occur until 0.03 V, which is 0.2 V more negative than that predicted with Nernst equation. MPA modifier exerts a blocking effect for Cu deposition. The as-prepared Cu film appears in atomically smooth rectangular islands until 11th layer, where rippling features emerge. STM reveals a highly ordered c (2 × 2) structure characterized as adsorbed bisulfate anions on the copper layer. Sparsely distributed protrusions are imaged on top of the bisulfate structure, which could be MPA molecules. These described results are mostly observed with MAA-modified Au(100) electrode, and MAA accelerates Cu underpotential deposition but blocks Cu overpotential deposition.
