时间：2014年10月23日（星期四）上午09:15

地点：科技创新大楼C501室

学者：沙特阿卜杜拉国王科技大学 张西祥教授

报告摘要：

Functionalized graphene has been extensively studied with the aim of tailoring properties for gas sensors, superconductors, supercapacitors,nanoelectronics, and spintronics. A bottleneck is the capability to control the carrier type and density by doping. We demonstrate that a two-step process is an efficient way to dope graphene: create vacancies by highenergy atom/ion bombardment and fill these vacancies with desired dopants. Different elements (Pt, Co, and In) have been successfully doped in the single-atom form. The high binding energy of the metal-vacancy complex ensures its stability and is consistent with in situ observation by an aberration-corrected and monochromated transmission electron microscope.

In addition, the interaction between single noble metal atoms and graphene edges has also been investigated the low-voltage TEM. A collective motion of the Au atom and the nearby carbon atoms is observed in transition between energy-favorable configurations. Most trapping and detrapping processes are assisted by the dangling carbon atoms, which are more susceptible to knock-on displacements by electron irradiation. Thermal energy is lower than the activation barriers in transition among different energy-favorable configurations, which suggests electron-beam irradiation can be an efficient way of engineering the graphene edge with metal atoms.

References

[1] H. T. Wang, Q.X. Wang,Y. C. Cheng, K. Li, Y. B. Yao, Q. Zhang, C. Z.Dong, P. Wang, U. Schwingenschlogl, W. Yang and X. X. Zhang, Nanolett. 12, 141?144(23012).      

[2] H. T. Wang, K. Li,Y. C. Cheng, Q.X. Wang, Y.B. Yao, U. Schwingenschlogl,X.X. Zhang and W. Yang, Nanoscale, 2012, 4, 2920

学者简介：

张西祥教授于1992年在巴塞罗那大学获得博士学位，95年于巴塞罗那大学任资深研究科学家，97年在香港科技大学任教授，2008年之后在阿卜杜拉国王科技大学任职教授。先后获得北京市科学技术一等奖、国家自然科学二等奖等奖项。他的研究领域涵盖磁性材料，磁输运，自旋电子学，磁制冷材料，多铁材料，石墨烯，碳基材料以及生物材料等。发表文章350余篇, 他引次数超过11000次, H因子=53.