Strain-Induced Electronic Structure Changes in Stacked van der Waals Heterostructures.
Vertically stacked van der Waals heterostructures composed of compositionally different two-dimensional atomic layers give rise to interesting properties due to substantial interactions between the layers. However, these interactions can be easily obscured by the twisting of atomic layers or cross-contamination introduced by transfer processes, rendering their experimental demonstration challenging. Here, we explore the electronic structure and its strain dependence of stacked MoSe2/WSe2 heterostructures directly synthesized by chemical vapor deposition, which unambiguously reveal strong electronic coupling between the atomic layers. The direct and indirect band gaps (1.48 and 1.28 eV) of the heterostructures are measured to be lower than the band gaps of individual MoSe2 (1.50 eV) and WSe2 (1.60 eV) layers. Photoluminescence measurements further show that both the direct and indirect band gaps undergo redshifts with applied tensile strain to the heterostructures, with the change of the indirect gap being particularly more sensitive to strain. This demonstration of strain engineering in van der Waals heterostructures opens a new route toward fabricating flexible electronics.
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.|School of Physical Science and Technology, Lanzhou University , Lanzhou, Gansu 730000, P. R. China.
Yongmin
Y
He
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Yang
Y
Yang
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.|State Key Laboratory of Mechanics and Control of Mechanical Structures, Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, Nanjing University of Aeronautics and Astronautics , Nanjing 210016, China.
Zhuhua
Z
Zhang
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.|Department of Chemistry, Rice University , Houston, Texas 77005, United States.
Yongji
Y
Gong
Materials Science & Technology Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
Wu
W
Zhou
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Zhili
Z
Hu
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Gonglan
G
Ye
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Xiang
X
Zhang
Department of Chemistry, Rice University , Houston, Texas 77005, United States.
Elisabeth
E
Bianco
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Sidong
S
Lei
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Zehua
Z
Jin
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Xiaolong
X
Zou
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Yingchao
Y
Yang
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Yuan
Y
Zhang
School of Physical Science and Technology, Lanzhou University , Lanzhou, Gansu 730000, P. R. China.
Erqing
E
Xie
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Jun
J
Lou
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Boris
B
Yakobson
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Robert
R
Vajtai
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Bo
B
Li
Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Pulickel
P
Ajayan
Stacked van der Waals heterostructures; chemical vapor deposition; controlled orientation and stacking order; electronic band structure interaction; photoluminescence; strain