Tunable Carrier Multiplication and Cooling in Graphene
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- 作者：Jens Christian Johannsen ; S酶ren Ulstrup ; Alberto Crepaldi ; Federico Cilento ; Michele Zacchigna ; Jill A. Miwa ; Cephise Cacho ; Richard T. Chapman ; Emma Springate ; Felix Fromm ; Christian Raidel ; Thomas Seyller ; Phil D. C. King ; Fulvio Parmigiani ; Marco Grioni ; Philip Hofmann
- 刊名：Nano Letters
- 出版年：2015
- 出版时间：January 14, 2015
- 年：2015
- 卷：15
- 期：1
- 页码：326-331
- 全文大小：403K
- ISSN：1530-6992
文摘
Time- and angle-resolved photoemission measurements on two doped graphene samples displaying different doping levels reveal remarkable differences in the ultrafast dynamics of the hot carriers in the Dirac cone. In the more strongly (n-)doped graphene, we observe larger carrier multiplication factors (>3) and a significantly faster phonon-mediated cooling of the carriers back to equilibrium compared to in the less (p-)doped graphene. These results suggest that a careful tuning of the doping level allows for an effective manipulation of graphene鈥檚 dynamical response to a photoexcitation.