Probing the role of interlayer coupling and coulomb interactions on electronic structure in few-layer MoSe₂ nanostructures

Aaron J Bradley; Miguel M Ugeda; Felipe H da Jornada; Diana Y Qiu; Wei Ruan; Yi Zhang; Sebastian Wickenburg; Alexander Riss; Jiong Lu; Sung-Kwan Mo; Zahid Hussain; Zhi-Xun Shen; Steven G Louie; Michael F Crommie

doi:10.1021/acs.nanolett.5b00160

Probing the role of interlayer coupling and coulomb interactions on electronic structure in few-layer MoSe₂ nanostructures

Nano Lett. 2015 Apr 8;15(4):2594-9. doi: 10.1021/acs.nanolett.5b00160. Epub 2015 Mar 19.

Authors

Aaron J Bradley¹, Miguel M Ugeda¹, Felipe H da Jornada^{1

2}, Diana Y Qiu^{1

2}, Wei Ruan^{1

3}, Yi Zhang^{4

5}, Sebastian Wickenburg^{1

2}, Alexander Riss¹, Jiong Lu^{1

6}, Sung-Kwan Mo⁴, Zahid Hussain⁴, Zhi-Xun Shen^{5

7}, Steven G Louie^{1

2}, Michael F Crommie^{1

2

8}

Affiliations

¹ †Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States.
² ‡Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
³ §State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
⁴ ∥Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
⁵ ⊥Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States.
⁶ ∇Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore.
⁷ ■Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, United States.
⁸ ○Kavli Energy NanoSciences Institute, University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.

Abstract

Despite the weak nature of interlayer forces in transition metal dichalcogenide (TMD) materials, their properties are highly dependent on the number of layers in the few-layer two-dimensional (2D) limit. Here, we present a combined scanning tunneling microscopy/spectroscopy and GW theoretical study of the electronic structure of high quality single- and few-layer MoSe2 grown on bilayer graphene. We find that the electronic (quasiparticle) bandgap, a fundamental parameter for transport and optical phenomena, decreases by nearly one electronvolt when going from one layer to three due to interlayer coupling and screening effects. Our results paint a clear picture of the evolution of the electronic wave function hybridization in the valleys of both the valence and conduction bands as the number of layers is changed. This demonstrates the importance of layer number and electron-electron interactions on van der Waals heterostructures and helps to clarify how their electronic properties might be tuned in future 2D nanodevices.

Keywords: Coulomb interaction; STM/STS; graphene; quasiparticle bandgap; screening; transition metal dichalcogenide.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Chalcogens / chemistry
Electron Transport
Materials Testing / methods
Metal Nanoparticles / chemistry*
Metal Nanoparticles / ultrastructure
Molecular Probe Techniques*
Molybdenum / chemistry*
Selenium / chemistry*
Static Electricity

Substances

Chalcogens
Molybdenum
Selenium