我們用掃描穿隧顯微鏡(STM)探測θ-Al2O3/NiAl(100)底層的結構 以及鍍在其上的Au-Pt雙金屬團簇。在不同的設定時，電子會從針尖 穿隧到不同的氧化層並且顯示表面之下的結構。這可以藉由相對能階和樣品的空軌域來理解。利用氣相沈積法，我們在300 K 溫度下，將金以及白金原子連續的鍍上。後鍍的金屬加入已存在的團簇的比例會隨著鍍量增加。在0.06 ML Pt/θ-Al2O3/NiAl(100)表面上，後鍍上的金會加入已存在的團簇的比率從 43 % 降到 21 %。大部分的金形成純的單金屬團簇。相比之下，在0.22 ML Pt/θ-Al2O3/NiAl(100)表面上，此比率會從 52 % 上升到 71 %。在Pt/Au/θ-Al2O3/NiAl(100)表面上，後鍍上的0.17 ML Pt會加入先鍍上的0.13 ML金團簇的比率是 58 %。加熱到450 K，鍍量從1 ML降到0.3 ML。加熱到700 K，鍍量是0.2 ML。大部分的金屬擴散到基底。 We have probed the structures beneath the surface of thin film θ-Al2O3/NiAl(100) and Au-Pt bimetallic clusters on θ-Al2O3/NiAl(100) with a scanning tunneling microscope (STM). With different settings, electrons tunnel from tip to different oxide layers and show the morphology of the structures beneath the surface. It is understood by the related energy level and the unoccupied states of the sample. On θ-Al2O3/NiAl(100), Au and Pt atoms are sequentially vapor deposited at 300 K. The ratio for the later deposited metal joining existing clusters depends on the coverage. In the presence of 0.06 ML Pt on θ-Al2O3/NiAl(100) surface, the ratio for the later deposited Au joining the existing clusters is decreased from 43 % to 21 %. Most of the Au atoms form new pure clusters; in contrast, the ratio is increased on 0.22 ML Pt/θ-Al2O3/NiAl(100) surface from 52 % to 71 %. For Pt/Au/θ-Al2O3/NiAl(100), the ratio for the later deposited Pt (0.17 ML) joining existing Au clusters (0.13 ML) is 58 %. After annealing to 450 K, the coverage decreases from 1 ML to 0.3 ML. After annealing to 700 K, the coverage is 0.2 ML. Most of the metals diffuse to the substrate.
