Sol-gel derived aluminum doped nanocrystalline zinc oxide for hydrogen gas sensing

Aluminum doped zinc oxide (AZO) films were synthesized on alkali free glass substrates by sol-gel spin-coating method using two different precursors (zinc acetate and zinc nitrate). The results showed that the crystallite size decreased with increasing dopant concentration. The films were fabricated using zinc acetate (precursor 1) as a starting material show a pipe-like structure, which significantly influenced the properties of films. The gas sensing tests showed the highest dopant concentration, 3 at.% aluminum doped zinc oxide film has the smallest crystalline size, dense surface, lowest resistivity and highest gas sensitivity.