Effect of annealing on composition, structure and optical properties of SrHfON thin films

► Novel SrHfON thin films were prepared by RF magnetron reactive sputtering. ► SrHfON films remain amorphous after 900 °C annealing. ► Refractive index increases while extinction coefficient decreases after annealing. ► The annealed SrHfON films have higher ɛ1 and lower ɛ2 than as-deposited SrHfON film.