※ 引述《patrickk (好難抉擇)》之銘言： : 急問加入TiO2的半導體是哪一型的 : 我猜是p-type : 因為Ti+4沒有價電子 : 不知道這樣對不對?? : 說明一下這是研究所考題，原文如下 : What type of semiconductor is formed by increasing the amount of metal in : TiO2? ※ 引述《patrickk (好難抉擇)》之銘言： : 急問加入TiO2的半導體是哪一型的 : 我猜是p-type : 因為Ti+4沒有價電子 : 不知道這樣對不對?? : 說明一下這是研究所考題，原文如下 : What type of semiconductor is formed by increasing the amount of metal in : TiO2? Maybe we can discuss the question with the Co(2+)-doped TiO2 film. In TiO2, titanium/oxygen bonds are primarily ionic, but slightly covalent. Each titanium gives four electrons to oxygen neighbors and each oxygen atom takes two electrons from titanim neighbors, but covalent character causes them to share electrons. Moreover, each oxygen atom pulls two electrons from two different titanium atoms, so from geometrical considerations we have reason to believe that an oxygen vacancy adjacent to a cobalt atom should compensate for only one electron charge at the cobalt site and leave an adjacent titanium atom with an extra electron. In fact, these kind of oxygen vacancies material can generate polarons(but not all), which may be mediating ferromagnetism, and they generate charge carriers that make TiO2 an n-type semiconductor. --

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