Effect of substrate temperature on mechanical properties of diamond-like carbon films

Smooth diamond-like carbon films are fabricated by pulsed laser deposition at different substrate temperature. DLC films grown at room temperature exhibit excellent mechanical properties, their hardness and elastic modulus are 45 GPa and 290 GPa, and their friction coefficient and wear rate, at the condition of 80% RH, are 0.045 and 5.74×10-10 mm3·N-1·m-1 respectively. However, the hardness and modulus of films decrease with increasing the substrate temperature, at the same time, the friction coefficient and wear rate increase with the deposition temperature. Raman spectrum indicates that the carbon film grow at low temperature is typical tetrahedral diamond-like carbon film with high sp3 content (about 76.8%), and the sp3 content of the film reduces with temperature and the mechanical