Electronic dynamics in unoccupied states of graphene

石墨烯未占据状态下的电子动力学

• 批准号: 172968903
• 负责人: Professor Dr. Helmut Zacharias
• 金额: --
• 依托单位: Center for Soft Nanoscience (SoN)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/172968903?language=en
• 关键词: Electronic; dynamics; unoccupied; states; graphene

In this project the dynamics in unoccupied electronic states of graphene nanoribbons and graphene sheets grown on Ni(111), intercalated with Au, and on SiC(0001) will be investigated. Measurements of the lifetimes are performed as a function of energy above the Fermi level in the vicinity of the K and of the M points. Due to the high parallel momentum of the electrons in these parts of the Brillouin zone ultrashort XUV pulses obtained from high harmonic generation of Ti:sapphire laser radiation have to be employed for the photoemission out of the excited states. A two-dimensional delay-line detector with time-of-flight option enables us to measure also the momentum relaxation in the unoccupied bands. We expect a different behavior near the K and M points of the Brillouin zone. A temporal delay of the XUV probe pulses with respect to visible or UV pump pulses enables us to trace these dynamics. The effect of doping the graphene, which shifts the unoccupied bands with respect to the Fermi level, shall also be studied for substrates which only weakly interact with the graphene. Various co-operation partners within the Priority Program contribute to reach these goals by providing chemicals for the defined growth of nanoribbons, Gr/SiC samples and theoretical insight into the dynamic behavior.

在这个项目中，将研究与Ni（111）生长的石墨烯纳米纤维和石墨烯片的无占用电子状态的动力学，与AU插入，并将研究SIC（0001）。生命值的测量是在K和M点附近的费米水平以上的能量的函数进行的。由于在布里鲁因区域的这些部分的高平行动量，从高谐波生成的Ti：蓝宝石激光辐射中获得的光发射必须从激发态中用于光发射。带有飞行时间选项的二维延迟线检测器，使我们还可以测量未占用频段中的动量放松。我们期望在布里渊区的K和M点附近有不同的行为。 XUV探针脉冲相对于可见或紫外泵脉冲的时间延迟使我们能够追踪这些动力学。对于仅与石墨烯弱相互作用的底物，还应研究掺杂石墨烯的掺杂石墨烯的效果。优先级计划中的各种合作伙伴通过为纳米管，GR/SIC样本的确定生长提供化学品和对动态行为的理论见解，从而有助于实现这些目标。