Nanocomposites and nanomaterials

Impurity luminescence of the opal-ZnO nanocomposite
Ohiienko O.V., Moiseienko V.N., Shvets T.V.
Physics, Electronics and Computer Systems Department, Oles Honchar Dnipro National University. Prospect Gagarina, 72, Dnipro-49010, Ukraine. 
E-mail: kombi21251@outlook.com

The interest in nanostructures based on the direct-gap ZnO semiconductor (Eg=3.2±0.01 eV) is due to the possibility of creating efficient phosphors [1], as well as lasers in the ultraviolet region of the spectrum [2]. In addition, near the edge of intrinsic absorption, three luminescence bands are observed in the visible spectral region due to impurities Cu2+, Li+, Na+, and Fe3+ [3]. The initial opals (the position of the stop-band 483-537nm) were impregnated with an aqueous solution of zinc nitrate Zn(NO3)2 n H2O, followed by the release of zinc oxide in the pores during heat treatment in air [1]. The photoluminescence spectra of opal-ZnO nanocomposites were measured upon excitation by an LED with λex=407 nm. Luminescence was recorded in the [111] direction. A wide structured band was observed in the region of 500-750 nm. The parameters of 4 elementary spectral components at various levels of infiltration are determined. An increase in the integrated intensity of all bands by 8 times with 3 cycles of impregnation was observed. The band in the region of 525-575 nm was most intense. The amplification in this case is due to the coincidence of the spectral position of the band maximum with the long-wavelength edge of the opal stop-band, where the maximum density of optical states takes place. In addition, the previously observed effect of pushing out the luminescence band from the stop-band was manifested. Taking into account the latter, the nature of this band can be associated with radiative transitions in Cu2+ impurity ions replacing Zn atoms [3].

1.	Gruzintsev A.N, Yemel'chenko G.A., Masalov V.M. Fotolyuminestsentsiya ZnO, infil'trovannogo v trekhmernyy fotonnyy kristall // Fizika i tekhnika poluprovodnikov.-2009.-43, N 8.-P. 1054-1059.
2.	Gruzintsev A.N., Yemel'chenko G.A., Red'kin A.N., Volkov V.T., Yakimov Ye.Ye., Visimberga D. Modovaya struktura izlucheniya lazerov iz nanosterzhney ZnO s odnim metallicheskim zerkalom // Fizika i tekhnika poluprovodnikov.- 2010.-44, N 9.-P. 1274-1279.
3.	Gavrilenko V.I., Grekhov A.M., Korbutyak D.V., Litovchenko V.G. Opticheskiye svoystva poluprovodnikov // Spravochnik. Kiyev, Naukova dumka, 1987