Low temperature mechanical properties of nanocrystalline diamond films

Measurements of the mechanical properties - internal friction and shear modulus - of several nanocrystalline diamond films grown on silicon resonator substrates is reported. The internal friction measurements of 0.5 mum boron-doped and boron-free nanocrystalline diamond films show that the boron concentration does not appear to be correlated with the previously reported internal friction peak at 1-2 K. Rather, a heavily boron-doped film appears to have an internal friction peak at 10 K. The low-temperature internal friction of these films is consistent with that of films reported upon earlier, and is in the range 2 times 10^-6 les Q^-1 les 6 times 10^-6