Structural and physical characterisation of transparent conducting pulsed laser deposited In2O3–ZnO thin films

Abstract

Indium–zinc oxide thin films, with compositions ranging from In2O3 to ZnO, were prepared by pulsed laser deposition using a substrate temperature of 500 °C and an oxygen pressure of 10−3 mbar. X-Ray diffraction studies coupled with transmission electron microscopy revealed that the texture and the structure of the films are composition dependent with however a preferred orientation for all compositions, excluding In2O3 for consideration. As the Zn/(Zn + In) atomic ratio increased, the film structure evolved from cubic In2O3 to hexagonal ZnO via a hexagonal layered ZnkIn2Ok + 3 structure. An average transmittance of 85–90% in the visible region was obtained for all films independently of the composition. The maximum conductivity (σ = 1500 S cm−1) was reached for a film having an atomic ratio Zn/(Zn + In) = 0.5 (i.e. Zn2In2O5).