Heat Treatment Impact on the Properties of Na and N Dual Doped ZnO Thin Flms by Spray Pyrolysis

Nano-crystalline p-type dual acceptor doped ZnO (ZnO:(Na, N)) thin films are prepared through the spay pyrolysis technique using zinc acetate dehydrate as a starting material. The as-prepared films are annealed at different temperatures, 350 0C, 400 0C and 450 0C for 1 h. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray Spectroscopy (EDX), UV-VIS Spectroscopy and Hall measurement are used to study the structural, surface morphology, optical and electrical properties of the annealed films, respectively. As prepared ZnO:(Na, N) thin films at 350 0C exhibit p-type conductivity, while the samples annealed at 400 0C and 450 0C are converted in to n-type conductivity. The lowest resistivity of 5.60×10-2 Ω cm achieved with a high carrier concentration of 3.15×1018 cm-3 for the films annealed at 350 0C.