Electron Transfer from a Diamond (100) Surface to an Atmospheric Water Adlayer: A Quantum Mechanical Study
2007 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 111, no 37, 13804-13812 p.Article in journal (Refereed) Published
The possibility of electron transfer from a H-terminated diamond (100) surface to an electrochemically reducible wetting adlayer, including species normally found in the atmosphere, has been studied theoretically using first-principles DFT methods. This type of electron-transfer process is one commonly assumed to be a prerequisite for induced p-type conductivity within the diamond surface. A partial electron transfer from the (2 × 1) reconstructed, H-terminated (100) surface to a water adlayer, including oxonium ions and molecular oxygen (or ozone), was observed. Both atomic charge calculations and frontier orbital overlap analyses were used in estimating the degree of electron transfer, and a strong coupling was observed between these two observables. A diamond surface with a pure water adlayer did not show any observable electron transfer, whereas the presence of oxonium ions showed a slightly improved degree of electron transfer (0.16 e-). However, the presence of molecular oxygen, as well as ozone, was found to result in a much larger degree of electron transfer (0.32 vs 0.43 e-), and a combination of oxonium ion and oxygen (or ozone) resulted in further improvements (0.65 vs 0.68 e-). For these various chemical water adlayer compositions, sheet carrier densities of 1013 cm-2 were found, which are in line with experimental data reported in the literature.
Place, publisher, year, edition, pages
2007. Vol. 111, no 37, 13804-13812 p.
IdentifiersURN: urn:nbn:se:uu:diva-96590DOI: 10.1021/jp070565iISI: 000249501800025OAI: oai:DiVA.org:uu-96590DiVA: diva2:171216