Study of the Chemical Vapor Deposition of Nano-Sized Carbon Phases on {001} Silicon.

Different nano-sized phases were synthesized using chemical vapor deposition (CVD) processes. The deposition took place on {001} Si substrates at about 1150-1160 °C. The carbon source was thermally decomposed acetone (CH)CO in a main gas flow of argon. We performed experiments at two ((CH)CO + Ar)/Ar) ratios and observed that two visually distinct types of layers were deposited after a one-hour deposition process. The first layer type, which appears more inhomogeneous, has areas of SiO (about 5% of the surface area substrates) beside shiny bright and rough paths, and its Raman spectrum corresponds to diamond-like carbon, was deposited at a (CH)CO+Ar)/Ar = 1/5 ratio. The second layer type, deposited at (CH)CO + Ar)/Ar = a 1/0 ratio, appears homogeneous and is very dark brown or black in color and its Raman spectrum pointed to defect-rich multilayered graphene. The performed structural studies reveal the presence of diamond and diamond polytypes and seldom SiC nanocrystals, as well as some non-continuously mixed SiC and graphene-like films. The performed molecular dynamics simulations show that there is no possibility of deposition of sp-hybridized on sp-hybridized carbon, but there are completely realistic possibilities of deposition of sp- on sp- and sp- on sp-hybridized carbon under different scenarios.