Structural and Optical Properties of Nitrogen‐doped Zinc Oxide Thin Films Grown on Muscovite Mica Substrates Using Sol–Gel Process

Abstract

Nitrogen (N)‐doped zinc oxide (NZO) thin films were grown on muscovite mica substrates by sol–gel spin‐coating and their structural and optical properties were investigated for various N concentrations (0, 3, 6, 9, and 12 at. %). The surface morphologies of all the films exhibited granular structures consisting of spherical nano‐sized crystallites. The (1 0 0) and (0 0 2) diffraction peaks were observed at 0, 3, and 6 at. % N concentration, while the (1 0 0) peak could not be distinguished and the (0 0 2) peak intensities decreased gradually at the higher concentrations. The near‐band‐edge to deep‐level emission intensity ratio increased significantly with increasing N concentration up to 6 at. %. All the films exhibited an average transmittance of more than 75% in the visible region. The optical band gap and Urbach energy determined by the measured transmittance were obviously dependent on the N concentration.