TY - JOUR
T1 - Computational Study of Interstitial Hydrogen Atoms in Nano-Diamond Grains Embedded in an Amorphous Carbon Shell
AU - Amihai Silverman, Alon Hoffman & Joan Adler
JO - Communications in Computational Physics
VL - 4
SP - 843
EP - 858
PY - 2011
DA - 2011/09
SN - 9
DO - http://doi.org/10.4208/cicp.270110.290610a
UR - https://global-sci.org/intro/article_detail/cicp/7524.html
KW - 
AB - <p style="text-align: justify;">The properties of hydrogen atoms in a nano-diamond grain surrounded
by an amorphous carbon shell are studied with Tight Binding computer simulations.
Our samples model nano-diamond grains, of a few nanometers in size, that nucleate
within an amorphous carbon matrix, as observed in deposition from a hydrocarbon
rich plasma. The calculations show that the average hydrogen interstitial formation
energy in the amorphous region is lower than in the nano-diamond core, therefore
hydrogen interstitial sites in the in the amorphous region are more stable than in the
nano-diamond core. This formation energy difference is the driving force for the diffusion
of hydrogen atoms from nano-diamond grains into amorphous carbon regions.
An energy well was observed on the amorphous side of the nano-diamond amorphous
carbon interface: hydrogen atoms are expected to be trapped here. This scenario agrees
with experimental results which show that hydrogen retention of diamond films increases
with decreasing grain size, and suggest that hydrogen is bonded and trapped
in nano-diamond grain boundaries and on internal grain surfaces.</p>