Two-step growth of ZnO films with high conductivity and high roughness

A new method combining metal organic chemical vapor deposition (MOCVD) and E-beam evaporation technique was proposed to grow un-doped zinc oxide (ZnO) transparent conductive oxide (TCO) films with both textured rough surface and high conductivity. Such films were composed with two layers. The first one is the Sn-doped In2O3 (ITO) seed layer deposited on glass substrate by E-beam evaporation, and the second is the un-doped ZnO film grown on the ITO film by MOCVD. From the results, it could be found that the ITO seed layer plays an important role in improving the conductivity and surface roughness of the ZnO films. Compared to the un-doped ZnO films directly deposited on the glass substrates by MOCVD, the ZnO/ITO films present expected textured surface with good light scattering and high conductivity at relatively low growth temperatures (398–413 K). The H2 annealing at 473 K of the ZnO/ITO film grown at 408 K effectively enhances the electron mobility from 18.6 to 32.5 cm2/V s.