Stability of van der Waals Pt-Telluride thin films

Pt Tellurides have promising and exciting electrocatalytic properties and can be grown in the form of thin films on several substrates. However, controlling the stoichiometry of ultrathin Pt-telluride 2D materials by physical vapor deposition methods is a challenge because different Pt telluride compositional phases have varying thermal stability in vacuum. 

Temperature-programmed synchrotron photoemission spectroscopy provides insight into the synthesis conditions by thermal treatment. High-resolution photoemission measurements  performed at the beamline BACH by Prof. Matthias Batzill and his group from University of South Florida have enabled the identification, the preparation and provided reference data of different layered van der Waals phases: Pt₃Te₄, and Pt₂Te₂ starting from PtTe₂ thin films. 

Moreover, the chemical stability of the different compositional thin film phases was investingated by exposing the materials to partial oxygen pressure and air. The results show that only weak adsorption occurs on the the surface Te layer, but the pristine materials can be re-established by vacuum annealing. This excellent chemical stability is important for the practical applications.