We report the effect of the concentration of hydroxide ion adsorbed (OHad)
on indium tin oxide (ITO) in the electrodeposition of zinc oxide (ZnO) by p
otential modulation method. We found that by applying an optimal constant p
otential of -0.72 V, X-ray diffraction (XPD) peak intensity of crystalline
phase indicating ZnO (100) and ZnO (101) deposited in oxygen containing sol
ution was significantly higher than that of ZnO formed in oxygen free solut
ion. ZnO was islanding on ITO substrate in an oxygen free solution, while u
niform ZnO underwent bulk deposition with higher growth rate due to higher
concentration of OHad resulted from dissolved oxygen. Thus, morphological i
mages were in good agreement with the crystal structural analysis. In pulse
d potential method, several ZnO peaks in ex situ XRD analysis were obtained
on ITO substrate as optimal cathodic potential of -0.72 V for 5 s was supe
rimposed on off-time of 5 s at open-circuit potential in each cycle. When r
elatively shorter cathodic time of 1 s was applied, however, we did not obt
ain any XRD peak of ZnO, because it might be due to the lack of the critica
l concentration of OHad to form ZnO on the surface. (C) 2001 The Electroche
mical Society.