Effects of the inclination angle of polyethylene terephthalate substrate on mechanical, electrical, and optical properties of Al-doped ZnO coating film

A flat plate in the deposition stage is designed to be tilted flexibly to form an inclination angle between an ion beam and the direction normal to a polyethylene terephthalate (PET) substrate. Five kinds of PET/aluminum-doped zinc oxide specimen were prepared to examine the effects of inclination angle on the mechanical, electrical, optical properties. The relative intensity ratio (χ₁) and d-spacing values both decrease with increasing inclination angle; the reductions of these two parameters result in an increase in the residual stress. The variation of energy gap with inclination angle is the same as that shown by the carrier concentration, and exactly opposite to those of resistivity and carrier mobility.