F-doped ZnO by sol-gel spin-coating as a transparent conducting thin film

This paper reports a simple non-alkoxide sol-gel route for depositing F-doped ZnO thin film on glass substrates. Ammonium fluoride and zinc acetate were used as the dopant precursor and starting material for ZnO, respectively. After the first crystallization at 550A degrees C in air, the sol-gel spin coated ZnO:F thin films at a F concentration < 5 at. % showed a nanosized polycrystalline structure with a c-plane preferred orientation. The structures, electrical resistivity, carrier concentration, mobility and optical transmittance were strongly dependent on the F concentration. The F concentration > 5 at. % degraded the microstructures, electrical conductivity, and optical transmittance. The second post-heat-treatment at 450A degrees C in a reducing environment resulted in higher electrical resistivity than the first post-heat-treatment in air.