Interdisciplinary Nanoscience Center (iNANO), University of Aarhus, Ny Munkegade 118, DK-8000 Aarhus C, Denmark.
Phys Chem Chem Phys. 2012 Feb 14;14(6):2092-8. doi: 10.1039/c2cp22712f. Epub 2012 Jan 9.
The morphology and thermal stability of Ni and Co nanoclusters grown by physical vapour deposition on a reconstructed (1120) surface of α-Al(2)O(3) is investigated using non-contact atomic force microscopy (NC-AFM). NC-AFM images reveal that the clean α-Al(2)O(3)(1120) substrate adopts a characteristic (12 × 4) reconstruction when prepared in vacuum at high temperature. Subsequent deposition of Ni and Co onto this substrate at room temperature facilitates the growth of well-ordered metal nanocluster arrays with a preferred inter-cluster distance determined by the (12 × 4) periodicity of the substrate surface. The order in the cluster arrangement remains intact even upon annealing the system to temperatures up to 500 °C indicating a high resistance against sintering. The reconstructed α-Al(2)O(3)(1120) surface can, therefore, serve as an appropriate insulating template for studies of size-dependent magnetic or catalytic effects in a well-defined ensemble of metallic nanoclusters.
使用非接触原子力显微镜（NC-AFM）研究了通过物理气相沉积在α-Al(2)O(3)重构（1120）表面上生长的 Ni 和 Co 纳米团簇的形态和热稳定性。NC-AFM 图像表明，清洁的α-Al(2)O(3)(1120) 衬底在高温下真空中制备时采用特征（12 × 4）重构。随后在室温下将 Ni 和 Co 沉积到该衬底上，有利于形成具有由衬底表面（12 × 4）周期性确定的优选的簇间距离的有序金属纳米团簇阵列。即使将系统退火至高达 500°C 的温度，簇排列的有序性仍然保持完整，表明其对烧结具有很高的抵抗力。因此，重构的α-Al(2)O(3)(1120)表面可以作为适当的绝缘模板，用于在金属纳米团簇的明确定义的集合中研究尺寸相关的磁性或催化效应。
