具光觸媒特性之TNO透明導電膜研究

Research of photocatalytic properties in Nb-doped TiO2 transparent conducting films

蔡淑惠(Shu-hui Tsai)

指導教授 ： 李正中

國立中央大學/理學院/光電科學研究所/碩士(2011年)

摘要

透明導電膜在許多光電元件中都扮演著相當重要的角色，TNO 為二氧
化鈦(TiO2)摻雜鈮(Nb)，除了具有導電特性之外，由於TiO2 本身就具有光觸
媒效果，摻雜Nb 後能隙會變大可增加光催化效果，故TNO 薄膜將成為具
有潛力的材料。本論文研究的TNO薄膜是以脈衝式直流磁控濺鍍鍍製完成，
薄膜特性之分析包含不同退火溫度與不同鈮摻雜功率下的光學特性、電特
性、薄膜結構與元素組成特性。實驗結果顯示在退火370 ℃、鈮摻雜功率
為90W 下可得到最低電阻率1.26×10-3 Ω-cm，遷移率為1.46 cm2/V-s，載子
濃度為1.89×1021 cm-3，最佳的鈦/鈮原子比為6.12；可見光波段的平均穿透
率約為70%、吸收率小於10%。
光觸媒特性之分析則透過接觸角量測、亞甲基藍水溶液降解實驗來判
斷其光催化反應效果。隨著照光時間的增加，薄膜表面的接觸角越來越小，
由原來的疏水性變為親水性，鈮摻雜功率為90 W 的TNO 薄膜更在照光6
分鐘內小於10°，所有樣品在照光18 分鐘內接觸角都可以小於10°；同時在
照光過程中片電阻值幾乎不變。分解亞甲基藍水溶液的實驗可知道不同鈮
摻雜功率之TNO薄膜在照光後濃度變化速率與接觸角量測結果有相同的趨
勢，且與導電率成正相關。TNO 薄膜的導電性越好，載子就越容易傳輸，
所以光激發產生的電子電洞對就能越快擴散到表面進行光催化反應。

關鍵字

透明導電膜 ； 光觸媒

並列摘要

Nb-doped TiO2 (TNO) film is a material with conductivity and
photo-catalytic properties. This research includes two parts, first we investigated
the electrical and optical characteristics of the TNO films. The second part, we
have discussed the photo-catalytic effect. After annealing in vacuum at 370 ℃,
the phase of the deposited TNO film with 90W RF power was transited from
amorphous to anatase The resistivity is about 1.26×10-3 Ω-cm, Hall mobility
is about 1.46 cm2/V-s, and carrier concentration is about 1.89×1021 cm-3, and the
ratio of atom number of titanium and niobium is 6.12. The average
transmittance is about70% and the absorbance is less than 10% in visible
region.
The contact angle of TNO films decreased when the irradiation time
increased, which implies the surface property of TNO films are changed from
hydrophobic to hydrophilic after ultraviolet irradiation. Furthermore, the sheet
resistivity of films is rarely changed under ultraviolet irradiating. For different
niobium concentration TNO films, the methylene blue solution degradation
speed decreased following the sequence of the deposition power, 90W, 95W,
100W, 85W, 80W, which reveals the same tendency of the contact angle
measurement. The higher conductivity, the higher mobility of the carries, and
the photo-excitation of electron-hole pair spreading to the surface faster for the
photocatalytic reaction.

並列關鍵字

transparent conducting films ； photocatalytic ； TNO

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