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

100%

Kulyk B., Figà V., Kapustianyk V., Panasyuk M., Serkiz R., Demchenko P.

Acta Physica Polonica A

2013

vol. 123

issue 1

92-97

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.

Specific Features of Content Dependences for Energy Gap in In_{x}Tl_{1-x}I Solid State Crystalline Alloys

84%

Kashuba A., Piasecki M., Bovgyra O., Stadnyk V., Demchenko P., Fedorchuk A., Franiv A., Andriyevsky B.

Acta Physica Polonica A

2018

vol. 133

issue 1

68-75

A series of In_{x}Tl_{1-x}I (x=0.4-0.9) single crystalline solid state alloys were successfully synthesized by the vertical Bridgman method. For the first time the density functional theory based band structure calculations are performed and features of the band energy dispersion are discussed. Comparison with the experimental energy gap E_{g} obtained from the optical photoconductivity is discussed. An essential role of the localized defects and excitons in formation of the edge photoconductivity is analyzed. Relation between the crystal structure and photoconductivity of the materials studied is discussed. Also the origin of the principal valence and conduction bands is explored. Experimental measurements of the band gap E_{g} by the optical and photoconductivity methods have given opposite dependences with respect to the indium content x. Features of the photoconductivity spectra for different crystallographic directions have been discussed with taking into account the chemical bonds anisotropy.

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2 Acta Physica Polonica A

1 2018

1 2013

2 Demchenko P.

1 Andriyevsky B.

1 Bovgyra O.

1 Fedorchuk A.

1 Figà V.

1 Franiv A.

1 Kapustianyk V.

1 Kashuba A.

1 Kulyk B.

1 Panasyuk M.

1 Piasecki M.

1 Serkiz R.

1 Stadnyk V.

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

Specific Features of Content Dependences for Energy Gap in In_{x}Tl_{1-x}I Solid State Crystalline Alloys