Thickness Dependence of Electrical and Optical Properties of Sol Gel ZnO Coatings

Abstract

Single and multilayer transparent conducting zinc oxide film has
been prepared on boro silicate substrates by the sol gel dip coating
process. Bach layer was kept at 600^oC in a conventional fumace
for 15 min. The final coatings were then tempered under a flux of
forming gas (N₂/H₂) at 400^oC for 2 h. The coatings were characterized
by surface stylus profiling, optical spectroscopy (UV, near
IR) and combined Hall and van der Pauw techniques. The thickness,
sheet resistance, electrical resistivity, mobility and transmittance of
obtained ZnO coatings were studied as a function of dipping speeds
and the number of coatings. The film resistivity decreases as the
number of coatings increases while the carrier mobility increases.
The transmittance of ZnO multilayers is slightly decreased with
increasing the number of coatings.