Effect of In concentration in the starting solution on the structural and electrical properties of ZnO films prepared by the pyrosol process at 450 degrees C
Ms. Tokumoto et al., Effect of In concentration in the starting solution on the structural and electrical properties of ZnO films prepared by the pyrosol process at 450 degrees C, J NON-CRYST, 273(1-3), 2000, pp. 302-306
Undoped and indium-doped Zinc oxide (ZnO) solid films were deposited by the
pyrosol process at 450 degrees C on glass substrates From solutions where
In/Zn ratio was 2, 5, and 10 at.%. Electrical measurements performed at roo
m temperature show that the addition of indium changes the resistance of th
e films. The resistivities of doped films are less than non-doped ZnO films
by one to two orders of magnitude depending on the dopant concentration in
the solution. Preferential orientation of the films with the c-axis perpen
dicular to the substrate was detected by X-ray diffraction and polarized ex
tended X-ray absorption fine structures measurements at the Zn K edge. This
orientation depends on the indium concentration in the starting solution.
The most textured films were obtained for solutions where In/Zn ratio was 2
and 5 at.%. When In/Zn = 10 at.%, the films had a nearly random orientatio
n of crystallites. Evidence of the incorporation of indium in the ZnO latti
ce was obtained from extended X-ray absorption fine structures at the In an
d Zn K edges. The structural analysis of the least resistive film (Zn/In =
5 at.%) shows that In substitutes Zn in the wurtzite structure. (C) 2000 El
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