磁控鐵鈷/氧化鎳半球殼二維陣列之光子晶體禁帶

Abstract

我們利用週期性單層聚苯乙烯球陣列，製備鐵鈷/氧化鎳的半球殼陣列。這個二維磁性週期陣列有明顯的禁帶，為一良好的光子晶體。在我們的實驗中，室溫中在一個乾淨的玻璃基板上滴入直徑900 奈米的聚苯乙烯球膠體，他們會自組裝形成二維單層光子晶體。我們在聚苯乙烯球的光子晶體上蒸鍍10奈米的鎳金屬薄膜，接著光子晶體和鎳金屬薄膜在氬氣中進行退火處理450 ℃三個小時，此溫度高於聚苯乙烯球的沸點，因為聚苯乙烯球的蒸發我們的半球殼氧化鎳陣列就形成了。最後，半球殼氧化鎳陣列，利用高真空磁控濺鍍系統沈積上30奈米鐵鈷薄膜，而鐵鈷的重量百分比分別為 25％和75％。總結來說，我們已經證明了鐵鈷/氧化鎳半球殼陣列的光子晶體禁帶可以藉由外加磁場來加以控制。基本的物理機制歸因於外加磁場可以調控磁性鐵鈷薄膜的介電常數。這結果為建立新的光子晶體的磁光元件開啟了一個可能性。

FeCo/NiO half-shell arrays were fabricated based on the periodic monolayer polystyrene spheres. The two-dimensional magnetic periodic arrays form well-defined photonic crystals with pronounced stop bands. Quite interestingly, it is found that the stop bands can be tuned by an external magnetic field. In our experiment, the colloid of 900 nm-diameter periodic polystyrene spheres (PSS) was dropped on a clean glass substrate at room temperature, and they would self-assemble to form a two dimensional monolayer PC. The PSS PCs were deposited with 10 nm Ni film by evaporation. The PS and the Ni film were annealed in Ar gas at 450。C, a temperature higher than the boiling point of PS for three hours. The PSS were evaporated, and the half-shell array of NiO was formed. Finally, the half-shell NiO array was deposited with 30 nm FeCo film by a high vacuum magnetron sputtering system, and the weight percentages of Fe and Co were 25% and 75%, respectively. We have successfully demonstrated that the PC stop bands based on FeCo/NiO half-shell arrays can be manipulated by an external magnetic field. The underlying physics is attributed to the controllable dielectric constant of magnetic FeCo film when an external magnetic field is applied. The result shown here may open up a possibility for the creation of new magneto-optical devices based on photonic crystals.