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Structural analysis of Cd–Te–O films prepared by RF reactive sputtering

2008; Elsevier BV; Volume: 354; Issue: 31 Linguagem: Inglês

10.1016/j.jnoncrysol.2008.03.042

1873-4812

F. Caballero‐Briones, Juan Luis Ruiz de la Peña, A. Martel, A. Iribarren, O. Calzadilla, S. Jiménez‐Sandoval, A. Zapata‐Navarro,

Quantum Dots Synthesis And Properties

Crystalline and microcrystalline Cd–Te–O samples have been obtained by RF reactive sputtering from a CdTe target using N2O as oxidant. The growth conditions were substrate temperatures of 323 K, 573 K and 773 K and cathode voltage of −400 V, corresponding to 30 W of forward power. The samples were studied by micro-Raman spectroscopy, X-ray diffraction and optical transmittance. The films are remarkably transparent in the visible range, with transmittances about 88% at 400 nm and band gap energies above the absorption edge of the glass substrates. Although only the samples prepared at 773 K present defined diffraction peaks, the analysis of the Raman spectra indicate that samples prepared at 323 K and 573 K have a defined microstructure indeed. The spectra fitting performed by comparison with pattern compounds demonstrate that Cd–Te–O films are formed of Te–O units similar to those present in metal oxide-doped tellurite glasses, such as TeO3 and TeO3 + 1 linked through Cd–O bonds. As the substrate temperature increases the microstructure evolves from a γ-TeO2 richer state to CdxTeyOz. In the crystalline sample the main phase identified was CdTeO3 even though evidence of other phases was observed.