Ostendorf F, Schmitz C, Hirth S, Kühnle A, Kolodziej J J, Reichling M
Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49076 Osnabrück, Germany.
Nanotechnology. 2008 Jul 30;19(30):305705. doi: 10.1088/0957-4484/19/30/305705. Epub 2008 Jun 12.
Muscovite mica is an important mineral that has become a standard substrate, due to its easy cleavage along the {001} planes, revealing a very flat surface that is compatible with many biological materials. Here we study mica surfaces by dynamic atomic force microscopy (AFM) operated in the non-contact mode (NC-AFM) under ultra-high vacuum (UHV) conditions. Surfaces produced by cleaving in UHV cannot be imaged with NC-AFM due to large surface charges; however, cleavage in air yields much less surface charge and allows for NC-AFM imaging. We present highly resolved NC-AFM images of air-cleaved mica surfaces revealing a rough morphology originating from a high density of nanometre-sized particles. Among these particles, we find regularly shaped structures indicating the growth of crystallites on the surface. The contamination layer cannot be removed by degassing in UHV; even prolonged heating at a temperature of 560 K under UHV conditions does not yield an atomically flat surface.
白云母是一种重要的矿物，由于其易于沿{001}面解理，能展现出与许多生物材料兼容的非常平整的表面，已成为一种标准衬底。在此，我们通过在超高真空（UHV）条件下以非接触模式（NC-AFM）操作的动态原子力显微镜（AFM）研究云母表面。在超高真空下通过解理产生的表面由于表面电荷较大，无法用非接触原子力显微镜成像；然而，在空气中解理产生的表面电荷要少得多，从而可以进行非接触原子力显微镜成像。我们展示了空气解理云母表面的高分辨率非接触原子力显微镜图像，揭示了由高密度纳米级颗粒产生的粗糙形态。在这些颗粒中，我们发现了规则形状的结构，表明表面有微晶生长。污染层不能通过在超高真空下脱气去除；即使在超高真空条件下于560 K的温度下长时间加热也不会产生原子级平整的表面。
