TY - JOUR
T1 - Impurities and Electronic Property Variations of Natural MoS 2 Crystal Surfaces
AU - Addou, Rafik
AU - McDonnell, Stephen
AU - Barrera, Diego
AU - Guo, Zaibing
AU - Azcatl, Angelica
AU - Wang, Jian
AU - Zhu, Hui
AU - Hinkle, Christopher L.
AU - Quevedo-Lopez, Manuel A.
AU - Alshareef, Husam N.
AU - Colombo, Luigi
AU - Hsu, Julia W P
AU - Wallace, Robert M.
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: Consejo Nacional de Ciencia y Tecnología[NL-2010-C33-149216]
PY - 2015/8/27
Y1 - 2015/8/27
N2 - Room temperature X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICPMS), high resolution Rutherford backscattering spectrometry (HR-RBS), Kelvin probe method, and scanning tunneling microscopy (STM) are employed to study the properties of a freshly exfoliated surface of geological MoS2 crystals. Our findings reveal that the semiconductor 2H-MoS2 exhibits both n- and p-type behavior, and the work function as measured by the Kelvin probe is found to vary from 4.4 to 5.3 eV. The presence of impurities in parts-per-million (ppm) and a surface defect density of up to 8% of the total area could explain the variation of the Fermi level position. High resolution RBS data also show a large variation in the MoSx composition (1.8 < x < 2.05) at the surface. Thus, the variation in the conductivity, the work function, and stoichiometry across small areas of MoS2 will have to be controlled during crystal growth in order to provide high quality uniform materials for future device fabrication. © 2015 American Chemical Society.
AB - Room temperature X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICPMS), high resolution Rutherford backscattering spectrometry (HR-RBS), Kelvin probe method, and scanning tunneling microscopy (STM) are employed to study the properties of a freshly exfoliated surface of geological MoS2 crystals. Our findings reveal that the semiconductor 2H-MoS2 exhibits both n- and p-type behavior, and the work function as measured by the Kelvin probe is found to vary from 4.4 to 5.3 eV. The presence of impurities in parts-per-million (ppm) and a surface defect density of up to 8% of the total area could explain the variation of the Fermi level position. High resolution RBS data also show a large variation in the MoSx composition (1.8 < x < 2.05) at the surface. Thus, the variation in the conductivity, the work function, and stoichiometry across small areas of MoS2 will have to be controlled during crystal growth in order to provide high quality uniform materials for future device fabrication. © 2015 American Chemical Society.
UR - http://hdl.handle.net/10754/594198
UR - https://pubs.acs.org/doi/10.1021/acsnano.5b03309
UR - http://www.scopus.com/inward/record.url?scp=84942134898&partnerID=8YFLogxK
U2 - 10.1021/acsnano.5b03309
DO - 10.1021/acsnano.5b03309
M3 - Article
C2 - 26301428
SN - 1936-0851
VL - 9
SP - 9124
EP - 9133
JO - ACS Nano
JF - ACS Nano
IS - 9
ER -