• 文献标题:   Tuning Ultrafast Charge Carrier Dynamics of Monolayer Graphene using Substrates
  • 文献类型:   Article
  • 作  者:   MENG SJ, SHI HY, SUN XD, GAO B
  • 作者关键词:  
  • 出版物名称:   JOURNAL OF PHYSICAL CHEMISTRY C
  • ISSN:   1932-7447 EI 1932-7455
  • 通讯作者地址:   Harbin Inst Technol
  • 被引频次:   0
  • DOI:   10.1021/acs.jpcc.0c06174
  • 出版年:   2020

▎ 摘  要

As monolayer graphene comprises only one single atomic layer, its physical and chemical properties could be easily tuned by the underlying substrate. However, it is still unknown how the distinct substrate influences the charge carrier dynamics of graphene, which is crucial for its optoelectronic and electrical properties. In this work, we investigated the charge carrier dynamics in monolayer graphene supported by hexagonal boron nitride (hBN), octadecyltrichlorosilane self-assembled monolayers (OTS SAMs), and glass using transient absorption microscopy. It is found that the charge carrier relaxation was tuned by these three substrates. The charge carriers decayed fastest on hBN, slowest on glass, and the decay rate was somewhere in between that on hBN and glass on OTS SAMs. The two-exponential fitting shows that this substrate-dependent charge carrier decay dynamics originated from the distinct hot phonon lifetime. Smaller electron-hole charge fluctuations, lower p-doping level, and larger thermal conductance are helpful for cooling the hot phonons and hence accelerating the charge carrier relaxation in monolayer graphene on hBN. These findings provide ideas for developing novel substrates to improve the performance of graphene-based electronic devices.