Hydrogen reverses the clustering tendency of carbon in amorphous silicon oxycarbide.
Amorphous silicon oxycarbide (SiOC) is of great technological interest. However, its atomic-level structure is not well understood. Using density functional theory calculations, we show that the clustering tendency of C atoms in SiOC is extremely sensitive to hydrogen (H): without H, the C-C interaction is attractive, leading to enrichment of aggregated SiC4 tetrahedral units; with hydrogen, the C-C interaction is repulsive, leading to enrichment of randomly distributed SiCO3 tetrahedral units. Our results suggest that conflicting experimental characterizations of C distributions may be due to differing amounts of H present in the samples investigated. Our work also opens a path for tailoring the properties of SiOC by using the total H content to control the C distribution.
1] Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 [2] Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China.
Hepeng
H
Ding
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139.
Michael J
MJ
Demkowicz