Preferential adsorption of thermally activated oxygen onto annealed polycrystalline diamond films studied by high resolution electron energy and X‐ray photoelectron spectroscopies

Abstract

In this work the amount of adsorbed oxygen and its chemical bonding configuration to diamond surface were investigated by X‐ray photoelectron spectroscopy (XPS) and high resolution electron energy loss spectroscopy (HR‐EELS), correspondingly. Hot filament chemical vapor deposited polycrystalline diamond films with sub‐micron grain size have been exposed in situ to thermally activated atomic oxygen (AO) and annealed in ultra‐high vacuum (UHV) in the range of 600–1000 °C. XPS studies revealed that substantial oxidation of the diamond surface takes place at TA > 800 °C, most likely owing to partial hydrogen desorption occurring at this temperature. HR‐EELS revealed that the main constituents of the surface after exposure to AO are saturated and unsaturated hydrocarbon species and oxygen‐bonded fragments. Oxygen bonds to diamond surface in ether (COC), peroxide (COOC), and carbonyl (CO) bonding. HR‐EELS features comparison of hydrogenated and oxygen exposed diamond surface as a function of thermal annealing suggests enhanced reactivity of hydrogenated diamond (111) facets as compared to (100) ones.

A Molecular View of Adsorption on Nanostructured Carbon Materials

“…256 On diamond surfaces, oxygen bonds in ether (C-O-C), peroxide (C-O-O-C), and carbonyl (C=O) bonding. 257 Adsorption of an O 2 molecule on a graphene sheet with and without a Stone-Wales defect was examined by the DFT. 258 The energetics have clarified that O 2 physisorption is possible for graphene with and without defects.…”