Diamond homoepitaxial films were grown on an off-angle (001) substrate
with a misorientation of 4.3 degrees toward the [110] direction by mi
crowave plasma-assisted chemical vapor deposition from a methane-hydro
gen gas mixture. The single domain 2x1 surface was observed by low-ene
rgy electron diffraction (LEED) and scanning tunneling microscopy, aft
er growth with methane concentration of 2%. With a methane concentrati
on of 6%, the LEED superstructure spot intensity from another domain i
ncreased, suggesting a higher rate of two-dimensional nucleation.