Rumpf K, Granitzer P, Hilscher G, Albu M, Poelt P
Institute of Physics, Karl Franzens University Graz, Universitaetsplatz 5, A-8010 Graz, Austria.
Microelectron Eng. 2012 Feb;90(C):83-87. doi: 10.1016/j.mee.2011.05.016.
Electrodeposition of ferromagnetic metals, a common method to fabricate magnetic nanostructures, is used for the incorporation of Ni structures into the pores of porous silicon templates. The porous silicon is fabricated in various morphologies with average pore-diameters between 40 and 95 nm and concomitant pore-distances between 60 and 40 nm. The metal nanostructures are deposited with different geometries as spheres, ellipsoids or wires influenced by the deposition process parameters. Furthermore small Ni-particles with diameters between 3 and 6 nm can be deposited on the walls of the porous silicon template forming a metal tube. Analysis of this tube-like arrangement by transmission electron microscopy (TEM) shows that the distribution of the Ni-particles is quite narrow, which means that the distance between the particles is smaller than 10 nm. Such a close arrangement of the Ni-particles assures magnetic interactions between them. Due to their size these small Ni-particles are superparamagnetic but dipolar coupling between them results in a ferromagnetic behavior of the whole system. Thus a semiconducting/ferromagnetic hybrid material with a broad range of magnetic properties can be fabricated. Furthermore this composite is an interesting candidate for silicon based applications and the compatibility with today's process technology.
铁磁金属的电沉积是制备磁性纳米结构的常用方法，用于将镍结构引入多孔硅模板的孔隙中。制备出的多孔硅具有多种形态，平均孔径在40至95纳米之间，相应的孔间距在60至40纳米之间。金属纳米结构在沉积工艺参数的影响下，以不同的几何形状沉积，如球形、椭球形或线状。此外，直径在3至6纳米之间的小镍颗粒可以沉积在多孔硅模板的壁上，形成金属管。通过透射电子显微镜（TEM）对这种管状排列进行分析表明，镍颗粒的分布相当狭窄，这意味着颗粒之间的距离小于10纳米。镍颗粒的这种紧密排列确保了它们之间的磁相互作用。由于这些小镍颗粒的尺寸，它们是超顺磁性的，但它们之间的偶极耦合导致整个系统呈现铁磁行为。因此，可以制备出具有广泛磁性的半导体/铁磁混合材料。此外，这种复合材料是基于硅的应用以及与当今工艺技术兼容性方面的一个有趣候选材料。
