Spectroscopic and morphological studies of SiO2 graded index thin films fabricated at oblique incidence angles

Abstract The present paper reports the fabrication of single layer graded index SiO2 thin films at various oblique incidence angles by using Static glancing angle deposition (GLAD) setup. These SiO2 films have been fabricated by using the electron-beam physical vapor deposition technique via ingeniously designed jig holder by placing the substrates at different angles of incidence of the incoming plasma. The optical properties of these films were studied by using UV–Vis–NIR spectrophotometer. The coating at various incidence angles of deposition from 10 to 80° reveals that there is a variation in refractive index of the material from 1.46 to 1.38. The microstructural studies of these films were further ascertained by field emission scanning electron microscopy, which reveals increase in the porosity of the film with deposition at oblique angle of incidence. The contact angle measurement of the films indicated the decrease in contact angle of these films with increasing angle of deposition indicating the hydrophilic nature of the samples. Owing to this behavior, these films find applications in antireflection (AR) coatings for flat panel displays, protective coatings, solar cells and optoelectronic devices etc.