本研究利用蛾眼效應，藉由多孔陽極氧化鋁蝕刻遮罩，在矽基板上製作出抗反射蛾眼結構。首先，我們先利用有限時域差分法設計出週期為200nm之奈米孔洞陣列作為蝕刻遮罩。然後，我們在矽基板表面製備多孔陽極氧化鋁奈米孔洞陣列薄膜，多孔陽極氧化鋁有著製做成本低廉，製程簡單、快速，以及容易大面積製作等優點。接著，我們利用高密度電漿蝕刻並通以SF6氣體，蝕刻矽基板表面。最後，我們在矽基板上製作出週期為220nm之奈米孔洞陣列抗反射結構。從實驗結果得知，當我們結構柱高高於500nm時，其反射率可低於1%，在我們製作的樣品中，反射率最好可低至0.58%，而當光源從60度入射時，反射率可低至3.01%。此外，我們也利用原子層沉積法，在結構表面鍍製ZnO薄膜，進一步地降低反射率。由模擬結果得知，當厚度達60nm時，有最佳優化抗反射之特性。我們最後讓一反射率為2.54%之樣品，在鍍製58nm之ZnO後，反射率降至0.83%。我們將抗反射結構應用於太陽能電池上，並將效率從4.311%提升至5.06%。In this study, we fabricated anti-reflection structure on silicon by using anodic aluminum oxide nanostructure as an etching mask inspired by moth eye effect. At first, we employed FDTD simulation to design the mask which is a nano-channel array with the period of 200nm. Then, anodic porous alumina membrane was used as the etching mask on silicon surface. Anodic porous alumina is a self-aligned structure with a submicron scale and easily formed by the anodic oxidation of Al over a large area and at low cost. After that the silicon was etched by high density plasma with SF6 gas. Finally, the anti-reflection nano-hole array structure with 220nm period was formed. The experiment results showed a low reflectivity below 1% was achieved over a wide spectral bandwidth from 400 to 1000 nm when nano-cone over 500nm. The best reflectivity can reach to 0.58% at normal incidence. When the angle of incidence is 60 degree, the best reflectivity can reach to 3.01%. In addition, an antireflection coating of ZnO film was deposited on the nanostructure using atomic layer deposition process to reduce surface reflection. According to our simulation result, a 60-nm thickness of ZnO is the best antireflection design. As a result, the average reflectance of the nanostructure with a single layer of ZnO can be decreased from 2.54% to 0.83%. Finally, the efficiency of the solar cell can increase from 4.31% to 5.06% by using the antireflection structure.
