Structural Properties and Temperature Behaviour of Optical Absorption Edge in Polycrystalline ZnO:X (Cu,Ag) Films

B. Kulyka, V. Figàb, V. Kapustianyka, M. Panasyuka, R. Serkiza, and P. Demchenkoc aScientific-Technical and Educational Center of Low Temperature Studies, Scientific and Educational Center "FRACTAL", Department of Physics, Ivan Franko National University of Lviv, Dragomanova Str., 50, UA-79005 Lviv, Ukraine bDepartment of Chemistry, University of Palermo, Viale delle Scienze - ed. 17, 90128 Palermo, Italy cDepartment of Inorganic Chemistry, Ivan Franko National University of Lviv, Kyryla i Mefodiya Street, 6, UA-79005 Lviv, Ukraine

Received: April 30, 2012

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Silver- and copper-doped ZnO films were prepared by radio-frequency magnetron sputtering on glass substrates. The influence of dopants content on the structural, morphological properties as well as on evolution of the optical absorption edge was considered. It has been found that Ag- and Cu-doped ZnO films are characterized by wurtzite crystalline structure with the preferred direction of crystalline orientation (002). The sizes of grains within the films were found to be dependent on the type of dopant. The temperature evolution of the optical absorption edge is described by the modified Urbach rule that reflects polycrystalline nature of the material. The corresponding parameters concerning electron- (exciton-) phonon interaction, phonon energies and temperature changes of the band-gap were determined and analysed.

DOI: 10.12693/APhysPolA.123.92 PACS numbers: 68.37.Ps, 78.40.Fy, 68.55.ag