| Autor: |
Punga, Luciana, Abbassi, Abderrahman, Toma, Mihaela, Alupului, Teodor, Doroftei, Corneliu, Dobromir, Marius, Tîmpu, Daniel, Doroftei, Florica, Hrostea, Laura, Rusu, George G., Razouk, Abdelati, Iacomi, Felicia |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
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| Popis: |
Highly transparent thin films with the chemical formula BaSrMgWO6 were deposited by spin coating using a solution of nitrates of Ba, Sr and Mg and ammonium paratungstate in dimethylformamide with a ratio Ba:Sr:Mg;W=1:1:1:1. XRD, SEM, EDX and XPS investigations evidenced that an annealing at 800 ºC for 1h leaves the structure amorphous with a precipitate on the surface and that a supplementary annealing at 850 ºC for 45 min forms a nanocrystalline structure and dissolves a part of precipitates. It was evidenced a textured double perovskite cubic structure (61.9%) decorated with tetragonal and cubic impurity phases (12.7 %) like BaO2, SrO2 and MgO and an under-stoichiometric phase (24.4%) with the chemical formula Ba2-(x+y) SrxMgyWO5. From transmittance measurements the values of optical band gap were estimated for the amorphous (Eg= 5.15) and nanocrystalline (Eg=4.58 eV) phases. The presence of a lattice disorder was indicated by the high values of Urbach and weak absorption tail energies A decrease in their values was observed and attributed to the crystallization process and cation redistribution. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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