Thermal desorption spectra of the oxidized surfaces of diamond powders

Abstract

Thermal desorption mass spectrometry was carried out in the range from room temperature to 960°C for the diamond powders oxidized in 10 −2Torr O 2 at temperatures from 25 to 554°C. The spectra show two desorption peaks (α, β) and the major peak α seems to consist of at least four types of adsorption states ( α 1− α 4). The first state α 1, may arise from “labile” carbon atoms created during degassing, and disappears with high temperature oxidation changing into the more stable states ( α 2- α 4). IR absorption spectroscopy shows that α 2− α 4 states include carbonyl and ether structures. The minor peak β shows little change with oxidation temperature. The amount of oxygen chemisorbed at 420°C (1.22 × 10 15 atom/cm 2) is in good agreement with the estimated value of full coverage.