ITO膜在不同pH溶液之循環電位掃瞄研究

The Behavior of Cyclic Voltammerty Stripping (CVs) of Tin-Doped Indium Oxide in Different Solutions

本研究主要探討一般視為n型半導體元件材料的ITO膜在採用0.3鹽酸、氫氧化鈉（6wt%）、氯化鈉（6wt%）水溶液以及純水四種測試液中，進行循環伏安掃瞄後的結果，在使用此四種不同的測試液檢測時當往負電位掃描皆有還原電流產生並形成一完整的峰值（peak），試片測試完成後表面經場射SEM觀察以及EDX成分分析，其結果可發現許多含大量銦錫元素的相析出於ITO膜上，隨著測試溶液的不同此銦錫化合物的形狀也跟著改變；而原本為晶粒–次晶粒（grain-subgrain）形貌的ITO膜表面在經過此還原反應後，基底呈現出十分明顯的沿晶界甚而整個基底解離。本研究結果中可以證實當ITO膜處在濕性環境且偏置負電位時十分的不穩定容易產生銦錫元素組成之還原反應物。

The purpose of this study is to research the electrochemical behavior of CVs (Cyclic Voltammetry stripping) for n-type semiconductor ITO-film in four different solutions: 0.3M HCl, 6 wt % NaOH, 6 wt % NaCl and D.I. water. When the potential of ITO-film was negatively polarized in the four solutions, an obvious reduction-current peak took place. After CVs test, the surfaces of samples were observed using FESEM integrated with EDS for chemical composition analysis. The result shows that many particles composed of indium and tin presented on ITO-film. The morphology of the particle was affected by the solution used. Due to different interfacial energy between particle and solutions, the shape of the particle can be in spherical, elliptic, or even flat form. The grain boundaries of ITO were the preferred dissolved site when the reduction current occurred.