High quality aluminium doped zinc oxide target synthesis from nanoparticulate powder and characterisation of sputtered thin films

• Nanoparticulate AZO powder was used to produce sputter targets.
• The powder synthesis technique allows for precise compositional control.
• Sputtered films show excellent optical, electronic and structural properties.
• High temperature films show reduced electrical and structural quality.
• For a given transmission, films show equivalent sheet resistances to ITO.

Nanoparticulate aluminium-doped zinc oxide powder was synthesised through detonation and subsequent rapid quenching of metallic precursors. This technique allows for precise compositional control and rapid nanoparticle production. The resulting powder was used to form sputter targets, which were used to deposit thin films by radio frequency sputtering. These films show excellent sheet resistance and transmission values for a wide range of deposition temperatures. Crystal structure analysis shows that crystals in the target have a random orientation, whereas the crystals in the films grow perpendicular to the substrate surface and propagate preferentially along the (002) axis. Higher temperature deposition reduces crystal quality with a corresponding decrease in refractive index and an increase in sheet resistance. Films deposited between room temperature and 300 °C were found to have sheet resistances equivalent to or better than indium tin oxide films for a given average transmission value.