On the optical properties of heat-treated multilayered Zn/In thin films

Zn/ln multilayered thin films (d = 70 - 110 nm) were deposited in vacuum onto unheated glass substrates, by staked layer technique. Metallic Zn and In were evaporated from independent and separated between them sources, maintained at 723 K for Zn and 570 K for In, respectively, during deposition. After preparation, the samples were heat-treated by annealing in air with a rate of 12 K/min from room temperature to 550 K. The as deposited samples present a polycrystalline hexagonal Zn (002) textured structure. The heat-treatment determines the formation of the hexagonal ZnO structure with highly (002) oriented crystallites. The optical transmittance in the wavelength range 380-1400 nm of the treated samples is about 85%. The optical band gap for respective samples is 3.18 eV.