Effect of doping concentration and annealing temperature on nitrogen-doped ZnO thin films: an investigation through spectroscopic techniques

Abstract

Undoped and nitrogen-doped ZnO (NZO) thin films were deposited by sol–gel spin-coating technique on glass substrates. The thin film preparation was accomplished using zinc acetate dihydrate, monoethanolamine and 2-methoxyethanol as the precursors. Ammonium acetate was used as the source of nitrogen for doping. The effect of dopants and the post-heating temperature on the various physical properties of the deposited films was explored. The X-ray diffraction studies reveal the polycrystalline nature of the films which possess a preferred c-axis orientation. Raman characterizations of the films show a clear indication of nitrogen incorporation in the films. The carrier concentration of the thin films was of the order of 1017/cm3 and resistivity as minimum as 0.371\xa0Ω\xa0cm was observed for 1\xa0at.% NZO thin films post-heated at 500\xa0°C. The 1\xa0at.% and 2\xa0at.% doped NZO films post-heated at 300\xa0°C and 1\xa0at.%, 2\xa0at.% and 3\xa0at.% doped NZO films with post-heat treatment at 500\xa0°C exhibited p-type conductivity. In the aging study, 500 °C annealed films retained p-type conductivity for 5\xa0days.