兆赫輻射時析頻譜於摻氮二氧化鈦薄膜之研究

Abstract

在本論文中，我們使用脈衝雷射蒸鍍法在矽基板上製備氮化鈦薄膜，並利用控氧系統對氮化鈦薄膜進行一系列不同條件的熱氧化處理來得到摻氮二氧化鈦薄膜。藉由XRD、AFM、XAS的量測來觀察氧化過程中樣品的晶格結構、表面樣貌及電子結構。之後透過本研究群所建立之兆赫輻射時析頻譜量測分析技術，研究摻氮二氧化鈦薄膜在此頻段下的電磁特性，由量測結果與理論分析可獲得薄膜樣品之複數折射率、介電係數及光學電導率隨樣品氮含量多寡變化的情形。結果顯示摻氮二氧化鈦薄膜對兆赫波段的響應較純二氧化鈦薄膜佳。

In this thesis, we have prepared nitrogen-doped TiO2 thin films by thermal oxidation of TiN thin films which were grown on Si(100) substrates by pulsed laser deposition(PLD). The surface morphology of samples with various oxidation time was studied by means of atomic force microscopy (AFM).The crystal structure and electronic states were investigated by means of x-ray diffraction (XRD) and x-ray absorption spectroscopy (XAS).The electromagnetic properties of nitrogen-doped TiO2 thin films at THz frequency have been studied by Terahertz Time-Domain-Spectroscopy (THz-TDS).The frequency dependence of the complex index of refraction, dielectric function and conductivity can be determined from the complex transmittance and Fresnel equation. The optical analysis revealed an additional absorption over THz range in nitrogen-doped TiO2 thin films.