Growth and characterization of indium doped zinc oxide films sputtered from powder targets

Indium doped ZnO films were grown on quartz glass substrates by radio frequency magnetron sputtering from powder targets. Indium content in the targets varied from 1at% to 9at%. In doping on the structure, optical and electrical properties of ZnO thin films were studied. X-ray diffraction shows that all the films are hexagonal wurtzite with c-axis perpendicular to the substrates. There is a positive strain in the films and it increases with indium content. All the films show a high transmittance of 86% in the visible light region. Undoped ZnO thin film exhibits a high transmittance in the near infrared region. The transmittance of indium doped ZnO thin films decreases sharply in the near infrared region, and a cut-off wavelength can be found. The lowest resistivity of 4.3×10^-4 Ω·cm and the highest carrier concentration of 1.86×10²¹ cm^-3 can be obtained from ZnO thin films with an indium content of 5at% in the target.