A type-I van der Waals heterobilayer of WSe2/MoTe2

Ming Li; Matthew Z. Bellus; Jun Dai; Liang Ma; Xiuling Li; Hui Zhao; Xiao Cheng Zeng

doi:10.1088/1361-6528/aac73a

A type-I van der Waals heterobilayer of WSe₂/MoTe₂

Ming Li
, Matthew Z. Bellus
, Jun Dai
, Liang Ma
, Xiuling Li
, Hui Zhao^*
, Xiao Cheng Zeng

^*Corresponding author for this work

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

42 Citations (Scopus)

Abstract

We present a joint theoretical/experimental study of a van der Waals heterobilayer with type-I band alignment formed by monolayers of WSe₂ and MoTe₂. Our first-principles computation suggests that both the valence band maximum and the conduction band minimum of the WSe₂/MoTe₂ heterobilayer reside in the MoTe₂ layer. The type-I band alignment allows efficient transfer of excitons from WSe₂ to MoTe₂. Since monolayer MoTe₂ is a direct semiconductor with a bandgap in the infrared range, this heterobilayer is attractive for infrared light emission applications. Time-resolved measurements of photocarrier dynamics were conducted to provide experimental evidence of the type-I nature of this heterobilayer. In these measurements, we found that excitation energy can transfer from WSe₂ to MoTe₂ efficiently, but not along the opposite direction. The efficient energy transfer can serve as an optical gain or wavelength conversion mechanism for efficient emission from MoTe₂, which can be utilized in ultrathin and efficient infrared light sources.

Original language	English
Article number	335203
Journal	Nanotechnology
Volume	29
Issue number	33
DOIs	https://doi.org/10.1088/1361-6528/aac73a
Publication status	Published - 13 Jun 2018
Externally published	Yes

Bibliographical note

Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

Research Keywords

density functional theory
energy transfer
transition metal dichalcogenide
ultrafast measurement
van der Waals heterostructure

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10.1088/1361-6528/aac73a

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Cite this

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title = "A type-I van der Waals heterobilayer of WSe2/MoTe2",

abstract = "We present a joint theoretical/experimental study of a van der Waals heterobilayer with type-I band alignment formed by monolayers of WSe2 and MoTe2. Our first-principles computation suggests that both the valence band maximum and the conduction band minimum of the WSe2/MoTe2 heterobilayer reside in the MoTe2 layer. The type-I band alignment allows efficient transfer of excitons from WSe2 to MoTe2. Since monolayer MoTe2 is a direct semiconductor with a bandgap in the infrared range, this heterobilayer is attractive for infrared light emission applications. Time-resolved measurements of photocarrier dynamics were conducted to provide experimental evidence of the type-I nature of this heterobilayer. In these measurements, we found that excitation energy can transfer from WSe2 to MoTe2 efficiently, but not along the opposite direction. The efficient energy transfer can serve as an optical gain or wavelength conversion mechanism for efficient emission from MoTe2, which can be utilized in ultrathin and efficient infrared light sources.",

keywords = "density functional theory, energy transfer, transition metal dichalcogenide, ultrafast measurement, van der Waals heterostructure",

author = "Ming Li and Bellus, \{Matthew Z.\} and Jun Dai and Liang Ma and Xiuling Li and Hui Zhao and Zeng, \{Xiao Cheng\}",

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T1 - A type-I van der Waals heterobilayer of WSe2/MoTe2

AU - Li, Ming

AU - Bellus, Matthew Z.

AU - Dai, Jun

AU - Ma, Liang

AU - Li, Xiuling

AU - Zhao, Hui

AU - Zeng, Xiao Cheng

N1 - Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

PY - 2018/6/13

Y1 - 2018/6/13

N2 - We present a joint theoretical/experimental study of a van der Waals heterobilayer with type-I band alignment formed by monolayers of WSe2 and MoTe2. Our first-principles computation suggests that both the valence band maximum and the conduction band minimum of the WSe2/MoTe2 heterobilayer reside in the MoTe2 layer. The type-I band alignment allows efficient transfer of excitons from WSe2 to MoTe2. Since monolayer MoTe2 is a direct semiconductor with a bandgap in the infrared range, this heterobilayer is attractive for infrared light emission applications. Time-resolved measurements of photocarrier dynamics were conducted to provide experimental evidence of the type-I nature of this heterobilayer. In these measurements, we found that excitation energy can transfer from WSe2 to MoTe2 efficiently, but not along the opposite direction. The efficient energy transfer can serve as an optical gain or wavelength conversion mechanism for efficient emission from MoTe2, which can be utilized in ultrathin and efficient infrared light sources.

AB - We present a joint theoretical/experimental study of a van der Waals heterobilayer with type-I band alignment formed by monolayers of WSe2 and MoTe2. Our first-principles computation suggests that both the valence band maximum and the conduction band minimum of the WSe2/MoTe2 heterobilayer reside in the MoTe2 layer. The type-I band alignment allows efficient transfer of excitons from WSe2 to MoTe2. Since monolayer MoTe2 is a direct semiconductor with a bandgap in the infrared range, this heterobilayer is attractive for infrared light emission applications. Time-resolved measurements of photocarrier dynamics were conducted to provide experimental evidence of the type-I nature of this heterobilayer. In these measurements, we found that excitation energy can transfer from WSe2 to MoTe2 efficiently, but not along the opposite direction. The efficient energy transfer can serve as an optical gain or wavelength conversion mechanism for efficient emission from MoTe2, which can be utilized in ultrathin and efficient infrared light sources.

KW - density functional theory

KW - energy transfer

KW - transition metal dichalcogenide

KW - ultrafast measurement

KW - van der Waals heterostructure

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DO - 10.1088/1361-6528/aac73a

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