Interaction of hydrogen and water with diamond (100): Infrared spectroscopy

Abstract

We report the first investigation of the adsorption of water on diamond (100) by infrared multiple-internal-reflection spectroscopy using a natural type IIa diamond internal reflection element. The first direct evidence of the diamond surface hydride structures, obtained by deuterium substitution, is also presented. Infrared evidence was seen for both monohydride and dihydride surface structures, with one or two hydrogen atoms per surface carbon atom (δCD mode at 901 cm−1 and δCD2 mode at 1125 cm−1, respectively). Following exposure to water at elevated temperature, infrared modes were detected at 1280, 1200, 1125, 1080, and 720 cm−1, and are assigned to ether (C—O—C), hydroxyl (C—OH), and carbonyl (≥C=O) modes. The substantial observed reactivity of diamond with water suggests a potentially important role for surface hydroxyl and oxide species in the surface chemistry and morphological development of diamond films grown by chemical vapor deposition.