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Atomic absorption photometry determination of excess Zn in ZnO

Svetlana Shinkarenko 2Tatjana Kirsanova 1Leo Türn 2Andrei Grebennik 1Anatoli Vishnjakov 1Kalju Lott 2

1. D.I.Mendeleyev University of Chemical Technology of Russia (MUCTR), Miusskaya sq. 9, Moscow 125047, Russian Federation
2. Tallinn University of Technology (TUT), Ehitajate tee 5, Tallinn 19086, Estonia


Zn excess in ZnO is built up automatically at high temperatures. Excess Zn in hydrothermally grown ZnO is investigated by the atomic absorption photometry (AAP) method. To determine the excess zinc in ZnO samples, the AAP of zinc vapour was used in the conditions of solid-vapour equilibrium. Optical absorbance of zinc, proportional to the concentration of zinc atoms in the vapour phase, was registered photoelectrically on the Zn resonance line. Zn AAP allowes to eliminate excess Zn connected differentially in ZnO samples. To fix Zn non-stoichiometry, all the ZnO samples tested were previously heat treated at temperature interval from 850 to 9000C and at fixed Zn vapour pressures from 0,1 to 0,9 of saturated zinc vapour pressure at given treatment temperature. Our AAP investigations in polycrystalline ZnS and ZnSe showed that the analytically determined concentration of Zn excess appears to be bigger than the concentration of electrically active defects. Zn adsorption on crystallite surfaces must be taken into account in ZnO also. The analysis of temperature dependence of zinc vapour pressure indicated that the value of zinc excess lies in the concentration interval of 1018 - 1019 cm-3 and depends on the sample biography and the conditions of preliminary heat treatment. Impurity metals take active role in the determination of non-stoichiometric zinc. The experimental results were used for preliminary high temperature defect equilibrium calculations for ZnO.


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Presentation: poster at E-MRS Fall Meeting 2004, Symposium F, by Kalju Lott
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-06-05 18:52
Revised:   2009-06-08 12:55