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Synthesis and Optical Properties of Different Bismuth Niobate Films Grown by Dual Magnetron Co‐Sputtering
Author(s) -
DepablosRivera Osmary,
Zeinert Andreas,
Rodil Sandra E.
Publication year - 2018
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201800269
Subject(s) - materials science , amorphous solid , sputter deposition , sputtering , thin film , bismuth , annealing (glass) , analytical chemistry (journal) , transmittance , optoelectronics , mineralogy , nanotechnology , crystallography , composite material , metallurgy , chemistry , chromatography
The interest about the synthesis of bismuth niobates (BNOs) in a thin‐film form has recently grown since their optical and electrical properties are attractive for applications such as photocatalysis, sensors, and fuel cells. The aim of this work is to demonstrate the successful synthesis of different BNOs as films using dual confocal magnetron co‐sputtering deposition, and evaluate properly their optical properties. Two independent targets of α‐Bi 2 O 3 and Nb are used. Crystalline as‐deposited films are obtained at Nb contents ≤9.2 at%. Meanwhile, films grow amorphous for Nb contents >9.2 at%. However, amorphous films are crystallized after annealing obtaining BNOs in compliance with the as‐grown composition. There is a good reproducibility and correlation between the films structure and composition that is controlled through the variation of the power applied to the Nb target. The following niobates are obtained: solid solutions with 5.1–6.6 at% Nb and II‐Bi 3 NbO 7 , Bi 5 Nb 3 O 15 , and the mixture of α‐BiNbO 4 (76 wt%) + β‐BiNbO 4 (24 wt%). The optical properties of the BNOs are estimated from the data measured by UV‐Visible‐NIR transmittance and reflectance spectrometry. It is shown that all the films have refractive indexes n >2 and optical gaps between 1.67 and 3.34 eV, depending on the Nb content and phase.