- 學位論文
奈米薄片之合成及應用於二氧化鈦-二氧化釩薄膜配向控制之特性研究
Studies on synthesis of exfoliate nanosheet and application on orientation control of TiO2-VO2 thin films
摘要
奈米薄片之製備及用於TiO2薄膜配向控制之研究，由於以簡單的化學溶液法製備具有配向性的薄膜之研究較少，因此，以奈米薄片作為模版之化學溶液法製備薄膜之研究更少。本研究一開始先合成無機層狀化合物，然後以化學剝離法製備奈米薄片分散液，其間以XRD 鑑定，無機層化合物在合成過程及剝離製程中的結晶型態，得到KCa2Nb3O10、HCa2Nb3O10相，以TEM分析所分離之奈米薄片Ca2Nb3O10 (CNO)之形貌為片狀，以SEM 及AFM 觀察奈米薄片黏貼於基板之狀況，藉此建立在基板上形成奈米薄片之製程。 接著利用化學溶液法製備二氧化鈦(TiO2)薄膜，以旋轉塗佈法在玻璃基板上鍍膜，並探討添加CNO奈米薄片對TiO2薄膜之影響。再以TiO2薄膜及TiO2-CNO薄膜為緩衝層製備二氧化釩(VO2)薄膜，提升VO2薄膜的光學特性。以XRD圖觀察得知TiO2薄膜隨著熱處理溫度升高，出現銳鈦礦相的(101)峰，然而添加CNO的TiO2薄膜具有優選方位(004)，表示CNO對TiO2薄膜配向性具有顯著的作用。 最後以TiO2薄膜及TiO2-CNO薄膜為緩衝層，成長VO2薄膜，藉由添加緩衝層提升VO2薄膜熱致色變特性。利用FTIR、四點探針進行光學及電性特性的量測。由XRD圖及FTIR的測量得知，VO2成長在TiO2及TiO2-CNO緩衝層上，可提升其結晶性並降低磁滯寬度。VO2薄膜電阻率在相變溫度前後的變化可達100倍左右。
並列摘要
The purpose of this thesis is to analyze preparation of exfoliate nanosheet and its applications on orientation control of TiO2 thin films. There are only a few studies on orientation controlled thin films prepared via simple chemical solution deposition. Therefore, there is little application of nanosheet on orientation control of thin film growth with chemical solution deposition. First of all, synthesis of an inorganic layered compound and exfoliate inorganic layered compound via chemical method, such as ion exchange and ion intercalation, can be used to prepare ceramic nanosheet. The crystal structure of layered compound were identified by XRD; KCa2Nb3O10 and HCa2Nb3O10 phase were obtained. TEM showed the exfoliated Ca2Nb3O10 (CNO) nanosheet was sheet-like shaped. SEM and AFM was used to observe the morphology of nanosheet attached on substrate. The nanosheet prepared on the substrate as a template layer. Secondly, TiO2 thin films were deposited on glass substrate by spin coating. The influence of TiO2 thin films with CNO additive was studied. The XRD pattern showed that TiO2 films prepared with CNO nanosheets demonstrated strong (004) peak with increasing annealing temperature, indicating that the c-axis preferential oriented TiO2 thin films were obtained. Experimental results showed that orientation preferred (004) of TiO2 thin films was influenced by CNO concentration and heat treatment temperature. Finally, VO2 thin films were deposited on glass substrates with TiO2 and TiO2-CNO thin films applied as buffer layers between the VO2 films and the substrates in order to investigate the effect of buffer layer on the formation and the thermochromic properties of VO2 film. In this case, electrical and optical properties were analyzed by FTIR, Four-point probe measurement. With TiO2 thin films and TiO2-CNO thin films as buffer layers, the crystallinity increased and reduced the transition temperature and hysteresis width (5°C). The resistance was varied with more than 2 orders under phase transition temperature.