Probing Co/Si interface behaviour by X-ray photoelectron spectroscopy （XPS） and atomic force microscopy （AFM）

In this work, we investigate the Co-Si reaction, the Co growth mode at room temperature, diffusion behaviour as well as morphology evolution during annealing on both H-terminated and clean Si（001） and Si（lll） surfaces. From in-situ X-ray photoelectron spectroscopy （XPS） investigation, ＂Co-Si＂ reaction appears to occur on both H-terminated and clean surfaces at room temperature （RT） and the silicide crystallinity is improved upon annealing. Co growth mode on H-terminated Si surfaces occurs in a pseudo layer-by-layer manner while small close-packed island growth mode is observed on the clean Si surface. Upon annealing at different temperatures, Co atom concentration decreases versus annealing time, which in part is attributed to Co atoms inward diffusion. The diffusion behaviour on both types of surfaces demonstrates a similar trend. Morphology study using ex-situ atomic force microscopy （AFM） shows that the islands formed on Si（001） surface after annealing at 700℃ are elongated with growth directions alternate between the two perpendicular [110 ] and [ 110] directions. Triangular islands are observed on Si （111） surface.     

Single DNA molecular manipulation with atomic force microscopy

Nanomanipulation of DNA molecules or other biomolecules to form artificial patterns or structures at nanometer scale has potential applications in the construction of molecular devices in future industries. It may also lead to new insights into the interesting properties and behavior of this fantastic nature-selected molecule at the single-molecular level. Here we present a special method based on the combination of macroscopic “molecular combing” and microscopic “molecular cutting” to manipulate DNA molecules and form complex patterns at nanometer scale on solid surfaces. A possible strategy for ordered DNA sequencing based on this nanomanipulation technique has also been proposed.     

碳微集团束的产生及其在CR-39中径迹的AFM观测

在HI－13串行加速器上实现了对碳微集团的加速,得到了MeV级的碳微集团束,对产生的碳的微集团束进行了测量并用它对CR＝－39塑料核径迹探测器进行了辐照,利用先进的原子力显微镜对C1和C2在CR－39中的径迹进行了观测。