Ultrafast Transient Absorption Microscopy Studies of Carrier Dynamics in Epitaxial Graphene

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• 作者：Libai Huang ; Gregory V. Hartland ; Li-Qiang Chu ; Luxmi ; Randall M. Feenstra ; Chuanxin Lian ; Kristof Tahy ; Huili Xing
• 刊名：Nano Letters
• 出版年：2010
• 出版时间：April 14, 2010
• 年：2010
• 卷：10
• 期：4
• 页码：1308-1313
• 全文大小：357K
• 年卷期：v.10,no.4(April 14, 2010)
• ISSN：1530-6992

文摘

Transient absorption microscopy was employed to image charge carrier dynamics in epitaxial multilayer graphene. The carrier cooling exhibited a biexponential decay that showed a significant dependence on carrier density. The fast and slow relaxation times were assigned to coupling between electrons and optical phonon modes and the hot phonon effect, respectively. The limiting value of the slow relaxation time at high pump intensity reflects the lifetime of the optical phonons. Significant spatial heterogeneity in the dynamics was observed due to differences in coupling between graphene layers and the substrate.