Occupied and unoccupied electronic structure of Na doped MoS₂(0001)

Authors

Takashi Komesu, Univesity of Nebraska - LincolnFollow
Duy Le, University of Central Florida
Xin Zhang, Univesity of Nebraska - LincolnFollow
Quan Ma, University of California
Eike F. Schwier, Hiroshima University
Yohei Kojima, Hiroshima University
Mintian Zheng, Hiroshima University
Hideaki Iwasawa, Hiroshima University
Kenya Shimada, Hiroshima University
Masaki Taniguchi, Hiroshima University
Ludwig Bartels, University of California
Talat S. Rahman, University of Central Florida
Peter A. Dowben, University of Nebraska-LincolnFollow

Date of this Version

2014

Citation

APPLIED PHYSICS LETTERS 105 (2014)

Comments

Copyrigth 2014 Used for permission

Abstract

The influence of sodium on the band structure of MoS₂(0001) and the comparison of the experimental band dispersion with density functional theory show excellent agreement for the occupied states (angle-resolved photoemission) and qualitative agreement for the unoccupied states (inverse photoemission spectroscopy). Na-adsorption leads to charge transfer to the MoS₂ surface causing an effect similar to n-type doping of a semiconductor. The MoS₂ occupied valence band structure shifts rigidly to greater binding with little change in the occupied state dispersion. Likewise, the unoccupied states shift downward, approaching the Fermi level, yet the amount of the shift for the unoccupied states is greater than that of the occupied states, effectively causing a narrowing of the MoS₂ bandgap.