AVS 66th International Symposium & Exhibition
    2D Materials Tuesday Sessions
       Session 2D+AS+MI+NS-TuM

Paper 2D+AS+MI+NS-TuM12
Surface Characterization of 2D Materials and their 3D Analogues using XPS

Tuesday, October 22, 2019, 11:40 am, Room A216

Session: 2D Materials Characterization including Microscopy and Spectroscopy
Presenter: Jonathan Counsell, Kratos Analytical Limited, UK
Authors: J.D.P. Counsell, Kratos Analytical Limited, UK
S.J. Coultas, Kratos Analytical Limited, UK
C.J. Blomfield, Kratos Analytical Limited, UK
N. Gerrard, Kratos Analytical Limited, UK
C. Moffitt, Kratos Analytical Limited
A.J. Roberts, Kratos Analytical Limited, UK
Correspondent: Click to Email
Since the synthesis of Graphene in 2004 there has been significant interest in novel 2D materials. Indeed this area has produced an abundance of high impact publications and so far >$10bn has been committed globally to both fundamental research and commercialisation. This interest has been due to the unique properties exhibited such as mechanical strength and charge/heat transfer. The potential commercial possibilities are diverse with applications as varied as heat management and dissipation to increasing computer processing power. To fully understand the nature and potential of these materials a comprehensive surface characterisation is necessary.

Herein we illustrate how by applying conventional surface analysis techniques with novel methodologies it is possible to create a more complete picture of the chemical and physical nature of deposited 2D materials. Both organic and inorganic 2D materials will be explored to demonstrate the methods and capabilities. Dichalcogenide materials (sulphides and selenides) containing different metal centres were analysed with XPS, and angular resolved methods, to calculate layer thicknesses, stoichiometry and chemical states. The lateral distribution of CVD ultra-thin films was studied using both macro and micro area XPS imaging modes to distinguish uniformity and evenness. The application of UPS will explore the bonding structure, sensitivity of the materials and as a potential tool for identifying damage/defects in the surface lattice. The merits and pitfalls of ion etching will be discussed and a complete method and protocol will be proposed for limiting spectral artefacts and therefore misleading results. The effects of deposition and analysis on the 2D materials’ structure and composition will be highlighted as will the characterisation of unwanted reduction/oxidation, contamination and structural defects. Utilising the complete surface analysis tool box allows the analyst to gain further insight and to fully understand the complex nature of these novel materials.