The study of transmittance spectra of ZnO and indium doped ZnO films

ZnO and indium doped ZnO films were prepared by radio frequency magnetron sputtering under strong magnetic field. The structure and morphology of the films were measured by X-ray diffraction and SEM, and the transmittance spectra of the films were measured by a double-beam ultraviolet/visible/near infrared spectrophotometer in the range of 300-2400nm. It was found that ZnO and indium doped ZnO films are hexagonal wurtzite structure with c-axis perpendicular to the substrates. ZnO film shows a smooth surface with intense grains, while the surface of indium doped ZnO film is rough with loose grains. Both ZnO and indium doped ZnO show high transmittance in the visible range and exhibit sharp adsorption edge in the ultraviolet. The low transmittance of indium ZnO film in the infrared region is attributed to high carrier concentration in the films, which is different from ZnO film.