Photoresponse of KNbO^sub 3^–AFeO^sub 3^ (A?=?Bi^sup 3+^ or La^sup 3+^) ceramics and its relationship with bandgap narrowing

The crystal structure of (1-x)KNbO3–xBiFeO3 (KNBF) and (1-x)KNbO3-LaFeO3 (KNLF) (where x = 0.00; 0.01; 0.02; 0.04; 0.08; 0.16; 0.32) was evaluated by XRD and Raman spectroscopy. XRD data show the crystal symmetry to evolve from orthorhombic to tetragonal with increasing x. The optical bandgap was fo...

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Bibliographic Details
Published in:Materials letters 2018-06, Vol.221, p.326
Main Authors: Elicker, Carolina, Pascual-González, Cristina, Gularte, Luciano T, Moreira, Mario L, Cava, Sergio S, Feteira, Antonio
Format: Article
Language:English
Subjects:
Ceramics
Crystal structure
Ferroelectrics
Materials science
Photovoltaic cells
Potassium
Potassium niobates
Raman spectroscopy
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Summary:The crystal structure of (1-x)KNbO3–xBiFeO3 (KNBF) and (1-x)KNbO3-LaFeO3 (KNLF) (where x = 0.00; 0.01; 0.02; 0.04; 0.08; 0.16; 0.32) was evaluated by XRD and Raman spectroscopy. XRD data show the crystal symmetry to evolve from orthorhombic to tetragonal with increasing x. The optical bandgap was found to narrow systematically with increasing x. Raman spectroscopy analysis corroborated long-range polar order in all compositions. The photoresponse of x = 0.32 shows a typical diode–like behaviour, with current and voltage of 0.115 µA and 0.075 V for KNBF and 0.19 µA and 0.035 V for KNLF, respectively. To our knowledge these represent the largest values among KNbO3–based ceramics, making them promising for photovoltaic applications.
ISSN:0167-577X
1873-4979