Nanotribological properties of ALD-processed bilayer TiO2/ZnO films

With respect to tribology, increased friction causes plastic deformation between the TiO2 and ZnO films, in addition to delamination and particle loosening. The plastic deformation caused by adhesion and/or cohesion failure is reflected in the nanoscratch traces. The pile-up events at a loading penetration of 30 nm were measured at 21.8 μN for RT, 22.4 μN for 300 °C, and 36 μN for 400 °C. In comparison to the other conditions, the TiO2/ZnO films annealed at 400 °C exhibited higher scratch resistance and friction with large debris, indicating the wear volume is reduced with increased annealing temperature and loading.