碲（Tellurium, Te）因具有優異的載子遷移率、窄能隙特性以及強烈的非線性光學響應，近年來受到半導體與光電領域的高度關注。
本研究以低溫蒸鍍法製備厚度分別為 10 nm、20 nm 及 30 nm 的碲薄膜，並沉積於二氧化矽（SiO₂）\聚醯亞胺（Polyimide, PI）\聚對苯二甲酸乙二酯（PET）基板上。利用傅立葉轉換紅外光譜儀（FTIR）、二倍頻量測系統（SHG）以及拉曼光譜（Raman spectroscopy）分析碲薄膜之光學特性，並透過基板彎曲方式施加機械應力，探討能隙、吸收係數、二倍頻強度及拉曼訊號之變化行為。FTIR 量測結果顯示，碲薄膜能隙隨厚度增加而下降。施加應力後，吸收係數明顯增加，部分樣品之能隙出現下降趨勢，且在解除應力後可恢復至接近原始狀態，顯示材料具有良好的可回復性。SHG 量測結果顯示碲薄膜具有顯著的非線性光學響應，其中 20 nm 樣品具有最高的二倍頻強度；隨著彎曲應力增加，parallel與cross條件下的二倍頻強度皆呈現下降趨勢。拉曼光譜分析則顯示不同厚度樣品具有明顯差異，並觀察應力是否會造成拉曼峰位移。
綜合實驗結果可知，碲薄膜之光學特性受到厚度與外加機械應力的顯著影響，有條件下具備可回復之特性。本研究證實碲薄膜具備應用於柔性光電子元件、非線性光學元件及應變感測元件之潛力。

Tellurium (Te) has attracted significant attention in semiconductor and optoelectronicresearch owing to its high carrier mobility, narrow bandgap, and strong nonlinear optical response. Due to its non-centrosymmetric crystal structure, Te is capable of generating second harmonic generation (SHG), making it a promising candidate for next-generation nonlinear optical and flexible optoelectronic devices. However, studies on the strain-dependent optical properties of Te thin films on flexible substrates remain limited.
In this study, Te thin films with thicknesses of 10 nm, 20 nm, and 30 nm were fabricated by thermal evaporation and deposited on silicon dioxide (SiO₂), polyimide (PI), and polyethylene terephthalate (PET) substrates. Fourier-transform infrared spectroscopy (FTIR), second harmonic generation (SHG), and Raman spectroscopy were employed to investigate the optical properties of Te thin films. Mechanical strain was introduced by substrate bending to explore the variations in bandgap, absorption coefficient, SHG intensity, and Raman response.
The FTIR results show that the bandgap of Te thin films decreases with increasing film thickness. After the application of strain, the absorption coefficient increased significantly, while some samples exhibited a reduction in bandgap. Upon strain release, the optical properties recovered to values close to their original states, indicating good recoverability of the material. SHG measurements revealed a pronounced nonlinear optical response in Te thin films, with the 20 nm sample exhibiting the strongest SHG intensity. Furthermore, the SHG intensity under both parallel and cross polarization configurations decreased with increasing bending strain. Raman spectroscopy results demonstrated thickness-dependent characteristics and revealed strain-induced Raman peak shifts.
In summary, the optical properties of Te thin films are strongly influenced by both film thickness and externally applied mechanical strain, and exhibit recoverable behavior under certain conditions. These findings demonstrate the potential of Te thin films for applications in flexible optoelectronic devices, nonlinear optical devices, and strain-sensing technologies.

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