Surface Analysis of WSe2Crystals: Spatial and Electronic Variability.
Layered semiconductor compounds represent alternative electronic materials beyond graphene. WSe2is one of the two-dimensional materials with wide potential in opto- and nanoelectronics and is often used to construct novel three-dimensional architectures with new functionalities. Here, we report the topography and the electronic property of the WSe2characterized by means of scanning tunneling microscopy and spectroscopy (STM and STS), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma mass spectrometry. The STM images reveal the presence of atomic-size imperfections and a variation in the electronic structure caused by the presence of defects and impurities below the detection limit of XPS. Both STS and photoemission reveal a spatial variation in the Fermi level position. The analysis of the core levels indicates the presence of different doping levels. The presence of a large concentration of defects and impurities has a strong impact on the electronic properties of the WSe2surface. Our findings demonstrate that the growth of controllable and high quality two-dimensional materials at nanometer scale is one of the most challenging tasks that requires further attention.
Department of Materials Science, Engineering, The University of Texas at Dallas , Richardson, Texas 75080, United States.
Rafik
R
Addou
Department of Materials Science, Engineering, The University of Texas at Dallas , Richardson, Texas 75080, United States.
Robert M
RM
Wallace
impurities; photoemission; scanning probe microscopy; surface defects; tungsten diselenide