Structural, electrical and luminescent properties of ZnO:Li films fabricated by screen-printing method on sapphire substrate

Undoped and Li‐doped ZnO thick films were fabricated by a screen‐printing technique on sapphire substrate. The effect of sintering temperature (TS = 800, 900 and 1000 °C) and Li content ([Li] = 0.003, 0.03 and 0.3 wt%) on the photoluminescence (PL), electrical and structural properties of the films was investigated. The X‐ray diffraction shows that all the films are polycrystalline with a wurtzite structure. It is found that both high sintering temperature and low Li content favour formation of the low‐resistive films with an enhanced UV emission. The high Li content stimulates an appearance of semi‐insulating behaviour of the films and deteriorated PL properties. It is shown that the effect of Li‐doping on light‐emitting properties of the films consists mainly in the modification of the film crystallinity and the engineering of the concentration of intrinsic defects. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)