Modification of Surface of ZnO:Mn Nanocrystals Synthesized by the Cryochemical Method

Authors О.V. Kovalenko , V.Yu. Vorovsky , M.F. Bulanyi , О.V. Khmelenko

Oles Honchar Dnipro National University, 72, Gagarin Avenue, 49010 Dnipro, Ukraine

Issue Volume 11, Year 2019, Number 5
Dates Received 19 June 2019; revised manuscript received 25 October 2019; published online 25 October 2019
Citation О.V. Kovalenko, V.Yu. Vorovsky, M.F. Bulanyi, О.V. Khmelenko, J. Nano- Electron. Phys. 11 No 5, 05034 (2019)
PACS Number(s) 75.50.Dd, 76.30.Fc, 61.05.cp
Keywords Diluted magnetic semiconductor (2) , ZnO (81) , Cryochemical (freeze-drying) method, Hydrogenation (2) , Ferromagnetism (7) .

The paper presents the results of studies of the effect of surface modification of ZnO:Mn nanocrystals obtained by cryochemical (freeze-drying) method on their physical characteristics. The modification was carried out by annealing the samples in the thermal decomposition products of polyvinyl alcohol, as well as in the hydrogen atmosphere. The concentration of Mn in the samples is 2, 4 and 8 at. %, respectively. It is found that modification of the surface of nanocrystals leads to an increase in their agglomeration properties. X-ray phase diffraction analysis and EPR (electron paramagnetic resonance) method showed that the solubility limit of Mn in ZnO nanocrystals does not exceed 4 at. %. Annealing of samples in the thermal decomposition products of polyvinyl alcohol increases the solubility limit of Mn. Thermal treatment of samples in a hydrogen atmosphere results in ferromagnetic properties at room temperature.

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