Electrical and optical properties of zinc oxide films post-annealed in H2 after fabrication by sol–gel process

摘要: Abstract Undoped ZnO films were post-annealed in hydrogen at 350 °C for 3 h after sol–gel spin-coating film fabrication followed by annealing from 500 to 575 °C, and their electrical optical properties investigated. The indicated c -axis oriented polycrystalline zinc oxide including metallic as interstitial atom the lattice well those before H 2 annealing. n-type semiconductors. minimum resistivity of was 0.22 Ω cm. Donor levels E d =0.04–0.08 eV estimated temperature dependence conductivity above 250 K. conduction mechanism shifted band ionized impurity scattering grain boundary temperatures between 250 300 K variable-range hopping below transparent visible range 400 nm had sharp ultraviolet absorption edges 380 nm. gap energy evaluated be opt =3.20–3.21 eV, width localized state e obtained =0.08–0.09 eV Urbach tail analysis.