利用脈衝雷射濺鍍之氧化鋅薄膜的製備與光學特性研究

Abstract

摘要 我們成功的利用氟化氪准分子脈衝雷射濺鍍在氧化鋁(Al2O3)晶片(0001)上成長出高指向性(002)面的氧化鋅薄膜，且在最佳的成長條件下有最小半高寬值為0.22度。在原子力顯微鏡的分析中，幾乎所有的氧化鋅薄膜都有良好的表面粗慥度。在低溫下的螢光光譜量測中，被中性施主束縛住的激子輻射強度大於其它的光譜；並且當環境溫度增加時，自由激子的輻射強度會漸漸的增加，最後在室溫下其強度為最強；激子和聲子產生交互作用下對激子半高寬變寬產生影響，其內容也被我們所討論。在拉曼散射光譜量測中，我們可以知道在氧化鋅薄膜結構中有過量的鋅原子存在；且分析結果也證明了螢光光譜量測中縱向性光學聲子複製。從室溫穿透光譜量測中，在最佳濺鍍條件下的氧化鋅薄膜的能隙值和氧化鋅靶材的值相似；且氧化鋅薄膜在氧壓一托耳的環境下有最好的薄膜品質，所得到的結果和之前X光繞射分析的結果相同，更能加以印證。最後，我們使用氧化鋅薄膜為模版，用氣-固機制的方式成功的長出六角形的奈米管。

Abstract We have successfully fabricated highly oriented (002) ZnO film which has a minimum FWHM of 0.22o in the optimum conditions on c-cut sapphire (0001) by pulsed laser deposition using KrF-excimer laser with a wavelength of 248 nm. Almost all of the films showed low surface roughness from AFM measurement. At low temperature PL, the neutral-donor bound exciton emission dominates the spectra, while with increasing temperature, free exciton emissions grow rapidly and finally become the dominant lines. The contribution of the exciton-phonon interaction to the exciton linewidth was studied. The Raman spectra indicated that the presence of excess zinc in the c-oriented ZnO structure and demonstrated LO-phonon replica in the PL spectra. From the transmittance measurement, the bandgap value of the as-deposited ZnO film for the optimum condition was similar to that of 3.37 eV for the ZnO bulk. The ZnO films have the best quality at oxygen pressure of 1 Torr consistent with result of XRD without quantum size effect. Finally, We successfully use of ZnO thin films as a template substrate to grow the hexagonal nanorods of ZnO with a vapor-solid mechanism.