Phonon Assisted Ultrafast Charge Transfer at van der Waals Interface
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- 英文论文题名：Phonon Assisted Ultrafast Charge Transfer at van der Waals Interface
- 论文作者：Qijing Zheng ; Wissam A.Saidi ; Yu Xie ; Zhenggang Lan ; Hrvoje Petek ; Jin Zhao
- 英文论文作者：Qijing Zheng ; Wissam A.Saidi ; Yu Xie ; Zhenggang Lan ; Hrvoje Petek ; Jin Zhao ; ICQD/Hefei National Laboratory for Physical Sciences at Microscale ; and Key Laboratory of Strongly-Coupled Quantum Matter Physics ; Chinese Academy of Sciences ; and Department of Physics ; University of Science and Technology of China ; Department of Mechanical Engineering and Materials Science ; University of Pittsburgh ; Key Laboratory of Biobased Materials ; Qingdao Institute of Bioenergy and Bioprocess Technology ; Chinese Academy of Sciences ; University of Chinese Academy of Sciences ; Department of Physics and Astronomy ; University of Pittsburgh ; Synergetic Innovation Center of Quantum Information & Quantum Physics ; University of Science and Technology of China
- 年：2016
- 作者机构：ICQD/Hefei National Laboratory for Physical Sciences at Microscale,and Key Laboratory of Strongly-Coupled Quantum Matter Physics,Chinese Academy of Sciences,and Department of Physics,University of Science and Technology of China;Department of Mechanical Engineering and Materials Science,University of Pittsburgh;Key Laboratory of Biobased Materials,Qingdao Institute of Bioenergy and Bioprocess Technology,Chinese Academy of Sciences;University of Chinese Academy of Sciences;Department of Physics and Astronomy,University of Pittsburgh;Synergetic Innovation Center of Quantum Information & Quantum Physics,University of Science and Technology of China;
- 英文论文关键词：vdW heterostructure ; ultrafast hole transfer ; phonon assisted ; ab-initio non-adiabatic molecular dynamics
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第四十分会：纳米体系理论与模拟
- 语种：英文
- 分类号：O47
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第四十分会 ; 纳米体系理论与模拟
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：46k
- 原文格式：D
- 会议级别：全国
摘要
The van der Waals interfaces of two-dimensional(2D) semiconductor are central to new device concepts and emerging technologies in light-electricity interconversion where the efficient charge separation is key factor. Contrary to general expectation, efficient electron-hole separation can occur in vertically stacked transition-metal dichalcogenide(TMD) heterostructure bilayers through ultrafast charge transfer between the neighboring layers despite their weak van der Waals(vd W) bonding. In this Letter, we show using ab initio non-adiabatic molecular dynamics(NAMD), that instead of direct tunneling, the ultrafast interlayer hole transfer is strongly promoted by an adiabatic mechanism through phonon excitation. At room temperature the interlayer charge transfer in MoS_2/WS_2 is ultrafast with a timescale of 20 fs which is in good agreement with the experiment. This ultrafast hole transfer process can be suppressed by decreasing the temperature to 100 K, which reduces the phonon occupation and the charge transfer is then dominated by direct tunneling, which happens at the time scale longer than 300 fs. The atomic level picture of phonon-assisted ultrafast mechanism revealed in our study is valuable both for the fundamental understanding of ultrafast charge carrier dynamics at vd W hetero-interfaces as well as for the design of novel quasi-2D devices for optoelectronic and photovoltaic applications.
The van der Waals interfaces of two-dimensional(2D) semiconductor are central to new device concepts and emerging technologies in light-electricity interconversion where the efficient charge separation is key factor. Contrary to general expectation, efficient electron-hole separation can occur in vertically stacked transition-metal dichalcogenide(TMD) heterostructure bilayers through ultrafast charge transfer between the neighboring layers despite their weak van der Waals(vd W) bonding. In this Letter, we show using ab initio non-adiabatic molecular dynamics(NAMD), that instead of direct tunneling, the ultrafast interlayer hole transfer is strongly promoted by an adiabatic mechanism through phonon excitation. At room temperature the interlayer charge transfer in MoS_2/WS_2 is ultrafast with a timescale of 20 fs which is in good agreement with the experiment. This ultrafast hole transfer process can be suppressed by decreasing the temperature to 100 K, which reduces the phonon occupation and the charge transfer is then dominated by direct tunneling, which happens at the time scale longer than 300 fs. The atomic level picture of phonon-assisted ultrafast mechanism revealed in our study is valuable both for the fundamental understanding of ultrafast charge carrier dynamics at vd W hetero-interfaces as well as for the design of novel quasi-2D devices for optoelectronic and photovoltaic applications.
The van der Waals interfaces of two-dimensional(2D) semiconductor are central to new device concepts and emerging technologies in light-electricity interconversion where the efficient charge separation is key factor. Contrary to general expectation, efficient electron-hole separation can occur in vertically stacked transition-metal dichalcogenide(TMD) heterostructure bilayers through ultrafast charge transfer between the neighboring layers despite their weak van der Waals(vd W) bonding. In this Letter, we show using ab initio non-adiabatic molecular dynamics(NAMD), that instead of direct tunneling, the ultrafast interlayer hole transfer is strongly promoted by an adiabatic mechanism through phonon excitation. At room temperature the interlayer charge transfer in MoS_2/WS_2 is ultrafast with a timescale of 20 fs which is in good agreement with the experiment. This ultrafast hole transfer process can be suppressed by decreasing the temperature to 100 K, which reduces the phonon occupation and the charge transfer is then dominated by direct tunneling, which happens at the time scale longer than 300 fs. The atomic level picture of phonon-assisted ultrafast mechanism revealed in our study is valuable both for the fundamental understanding of ultrafast charge carrier dynamics at vd W hetero-interfaces as well as for the design of novel quasi-2D devices for optoelectronic and photovoltaic applications.
引文