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Advances in Nano Research   Volume 5, Number 3, September 2017, pages 193-201
DOI: http://dx.doi.org/10.12989/anr.2017.5.3.193
 
ZnO thin films with Cu, Ga and Ag dopants prepared by ZnS oxidation in different ambient
Roberto Benjamín Cortés Herrera, Tetyana Kryshtab, José Alberto Andraca Adame and Andriy Kryvko

 
Abstract     [Full Text]
    ZnO, ZnO: Cu, Ga, and ZnO: Cu, Ga, Ag thin films were obtained by oxidization of ZnS and ZnS: Cu, Ga films deposited onto glass substrates by electron-beam evaporation from ZnS and ZnS: Cu, Ga targets and from ZnS: Cu, Ga film additionally doped with Ag by the closed space sublimation technique at atmospheric pressure. The film thickness was about 1 μm. The oxidation was carried out at 600-650°C in air or in an atmosphere containing water vapor. Structural characteristics were investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). Photoluminescence (PL) spectra of the films were measured at 30-300 K using the excitation wavelengths of 337, 405 and 457.9 nm. As-deposited ZnS and ZnS: Cu, Ga films had cubic structure. The oxidation of the doped films in air or in water vapors led to complete ZnO phase transition. XRD and AFM studies showed that the grain sizes of oxidized films at wet annealing were larger than of the films after dry annealing. As-deposited doped and undoped ZnS thin films did not emit PL. Shape and intensity of the PL emission depended on doping and oxidation conditions. Emission intensity of the films annealed in water vapors was higher than of the films annealed in the air. PL of ZnO: Cu, Ga films excited by 337 nm wavelength exhibits UV (380 nm) and green emission (500 nm). PL spectra at 300 and 30 K excited by 457.9 and 405 nm wavelengths consisted of two bands – the green band at 500 nm and the red band at 650 nm. Location and intensities ratio depended on the preparation conditions.
 
Key Words
    zinc oxide; zinc sulphide; oxidation; photoluminescence; x-ray diffraction
 
Address
(1) Roberto Benjamín Cortés Herrera:
Instituto Politécnico Nacional - ENCB, Prolongación de Carpio y Plan de Ayala s/n, Col. Santo Tomás, 11340, Ciudad de México, México;
(2) Tetyana Kryshtab:
Instituto Politécnico Nacional - ESFM, Av. IPN, U.P.A.L.M., Edif. 9, 07738, Ciudad de México, México;
(3) José Alberto Andraca Adame:
Instituto Politécnico Nacional - CNMN, Av. Luis Enrique Erro S/N, U.P.A.L.M., 07738, Ciudad de México, México;
(4) Andriy Kryvko:
Instituto Politécnico Nacional - ESIME Zacatenco, U.P.A.L.M., Av. IPN, U.P.A.L.M., Edif. Z-4, C.P. 07738, Cuidad de México, México.
 

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