TiO2/Ag/TiO2 複合多層膜特性分析與其光檢測器元件之應用

Fabrication and Characterization of TiO2/Ag/TiO2 Multilayer Films and Their Application to Photodetectors

林筱玫(Shiau-Mei Lin)

指導教授 ： 姬梁文

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2011年)

摘要

二氧化鈦為良好的半導體材料，其有較佳的穩定性、無毒價廉、光催化活性較高等優點；但TiO2能隙較寬(3.2 eV)，只能被紫外光激發，故應用光源比例低。本研究以貴金屬表面沉積減小二氧化鈦能隙，增加對可見光的吸收能力，改善二氧化鈦光觸媒與導電特性。第一部分：利用射頻磁控濺鍍系統與電子束蒸鍍系統，在康寧玻璃上製作(TiO2/Ag/TiO2，TAT) 奈米結構多層膜，由實驗分析得知Ag薄膜厚度為12 nm具有最薄的連續薄膜，藉由改變上下TiO2薄膜並經不同熱退火處理，探討不同厚度的TAT結構與光電特性，並利用場發射掃描式電子顯微鏡(FE-SEM)、原子力顯微鏡(AFM)對薄膜表面形貌進行分析，用紫外光-可見光光譜儀(UV-VIS)測試其透光性能。
第二部分：利用最佳化TAT結構來製作鈦金電極之光檢測器，在不同結構之光檢測器在5 V偏壓下暗電流為2.07 nA(TiO2)至82.5 nA(TAT)。TAT結構比TiO2薄膜使暗電流提升，証明TAT結構使導電度提升。
第三部分：使用化學水浴法在不同結構TAT與二氧化鈦薄膜合成二氧化鈦奈米柱，探討不同晶種層對於奈米柱形貌與光學特性的影響，且分析不同結構奈米柱之光偵測器。

關鍵字

二氧化鈦 ； 多層膜 ； 光檢測器 ； 二氧化鈦奈米柱

並列摘要

Titanium dioxide is the good material of semi-conductor. It has good chemical stability, non-toxicity, low cost, and high photocatalysis. However, the wide energy has band gap (3.2eV) and it’s excited only by ultraviolet range, pure TiO2 has very low photocatalytic efficiency. This study is attempted to deposit by precious metal and decreases the band-gap of TiO2. It was in order to raise the optical absorption properties in visible region and was in hope to improve the performance of photocatalytic properties and conductivity. The first part is that a TiO2/Ag/TiO2 nano multilayer film was grown on Corning glass substrate. It was used radio frequency (rf) magnetron sputter system and electron gun evaporator system. Ag film with approximately 12 nm is the thinnest single layer continuously from the experimental results. We could investigate the optical and electrical performance of TAT structure by transform TiO2 thin film. FE-SEM and AFM were used to characterize the surface morphology and UV-VIS transmittance spectra (UV-VIS) examine transmittance of the TAT nano multilayer films.
The second part is we could fabricate the Ti/Au electrodes of PDs with optimization of TAT structure and discuss about the characteristic. It can be found that dark current of different structure MSN-PDs were 2.07 nA (TiO2) to 82.5 nA (TAT) at 5 V bias. We could observe that conductivity of TAT structure has increase.
The third part is we discuss and demonstrate that TiO2 nanorod arrays were prepared on TiO2 and TAT seed layer by the chemical bath deposition has approached. The morphology of optical and electrical performance was obtained TiO2 nanorod arrays investigation for the different seed layer. Additionally, PDs with nanorod arrays have been fabricated and characterized.

並列關鍵字

TiO2 ； multilayer film ； photodetectors ； TiO2 nanorods

參考文獻

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