利用金屬氧化物和氧化鈦薄膜形成異質接面提升光觸媒特性之研究

Metal Oxide and Titanium Oxide Thin Film to Form a Heterojunction to Enhance the Photocatalytic Characteristics

洪亦佑(Yi-You Hong)

指導教授 ： 劉代山

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(2012年)

https://doi.org/10.6827/NFU.2012.00166

摘要

在本篇論文中，將使用電漿增強化學氣相沉積系統(PECVD)於200oC升溫環境下，沉積二氧化鈦薄膜於氧化鎳晶種層之上，並且使用高溫爐以600oC氧氣環境熱處理的方式，製備出具有銳鈦礦(Anatase)結構之多晶二氧化鈦薄膜。在形成p-n接面方面，使用了金屬蒸鍍系統沉積薄Ni、Cu金屬於氧化鈦薄膜上。再以適當溫度快速熱退火於氧氣環境下將Ni、Cu薄膜氧化成p型NiO、Cu2O薄膜，與n型的TiO2接觸，預期在接面處形成一p-n 接觸結構。此外，研究中並將在氧化鈦薄膜上以射頻磁控共濺鍍系統沉積ZnO薄膜，因為ZnO為n型半導體，與TiO2薄膜形成n-n 接面，做為本研究之對照組，比較其光觸媒特性是否因為有p-n 接面的產生而有所提升。
研究結果顯示，鎳金屬薄膜在550 oC氧氣熱處理後會形成p型氧化鎳薄膜；銅金屬薄膜在350oC氧氣熱處理後會形成p型氧化亞銅薄膜。在光觸媒降解實驗中，以氧化鈦/氧化鎳以及氧化鈦/氧化亞銅之異質接面結構薄膜，擁有最佳的光觸媒特性，亞甲基藍分解速率常數k(min-1)值分別為0.0327以及0.0312，且表面粗糙度分別為12.7 nm及7.1 nm。且從半導體參數量測分析中可發現，氧化鈦/氧化鎳以及氧化鈦/氧化亞銅之異質接面結構薄膜之光激發光電流量化數值與其它結構之氧化鈦薄膜相比，提昇倍率至少在10倍以上，且回歸暗電流之時間也延長將近一倍，有7分鐘之久，由於p-n接面的形成會延長受光激發後之電子-電洞對的再結合(recombination)時間，顯示出有p-n接面的存在，確實有助於提高氧化鈦薄膜的光觸媒特性。且由薄膜可靠度分析中可以發現，氧化鈦/氧化亞銅異質結構薄膜非常穩定，不易受到外在環境影響而改變其氧化型態，所以氧化鈦/氧化亞銅異質p-n結構薄膜之亞甲基藍降解再現性良好具有優異的光觸媒活性可靠度。

關鍵字

電漿增強化學氣相沉積系統 ； 銳鈦礦 ； p-n接面

並列摘要

In this study, deposition of titanium dioxide thin films by plasma enhanced chemical vapor deposition (PECVD) at 200oC temperature environment, on top of nickel oxide seed layers. And use high-temperature furnace to the 600oC oxygen heat treatment, preparation the titanium dioxide thin films with anatase structure of crystalline. In the formation of a p-n junction, used the metal evaporation system deposition of Ni、Cu metal on top of titanium dioxide thin film. Appropriate temperature rapid thermal annealing in oxygen environment of Ni、Cu thin film oxidation of p-type of NiO、Cu2O films with n-type TiO2 contact, it is expected that the formation of a p-n junction at the contact structure. In addition, the study and in the titanium dioxide film to the RF magnetron sputtering system of ZnO thin films, ZnO as the n-type semiconductor, and TiO2 thin film formed nn junction, as the control group in this study to compare the light touch media characteristics of the p-n junction to produce improved.
The results show that nickel metal thin film p-type nickel oxide film formed after 550 oC oxygen heat treatment; copper metal thin film in 350oC oxygen after heat treatment will form the p-type cuprous oxide film. In the photocatalytic degradation experiments, the titanium oxide / nickel oxide and titanium dioxide / cuprous oxide heterostructures film, with the best characteristics of the photocatalyst, the methylene blue decomposition rate constant k (min-1) values were 0.0327 and 0.0312, and the surface roughness of 12.7 nm and 7.1 nm, respectively. And can be found from the analysis of semiconductor parameter measurements, the titanium oxide / nickel oxide and titanium dioxide / cuprous oxide heterojunction structure of thin film optical excitation optical flow of value and other structure of titanium dioxide thin film compared to enhance the rate of at least more than 10 times, and return to the dark current of the time also extended nearly doubled seven minutes long, due to the formation of the p-n junction will be extended by the photoexcited electron-hole pairs recombination, showing the existence of a p-n junction, does help to improve the photocatalytic properties of titanium dioxide thin film. And reliability analysis by the film can be found in the titanium dioxide / cuprous oxide heterostructure film is very stable, less susceptible to the external environment and change their type of oxidation, so the titanium dioxide / cuprous oxide heterojunction p-n structure of thin films of the degradation of methylene blue reproduction good with excellent photocatalytic activity reliability.

並列關鍵字

Plasma Enhanced Chemical Vapor Deposition ； Anatase ； p-n junction

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