Disclosing the nature of vacancy defects in ?-Ag2WO4

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Assis, M. ; Castro, M. S. ; Aldao, C. M. ; Buono, C. ; Ortega, P. P. ; Teodoro, M. D. ; Andres, J. ; Gouveia, A. F. ; Simoes, A. Z. ; Longo, E. ; Macchi, C. E. ; Somoza, A. ; Moura, F. ; Ponce, M. A.

• Tipo de documento: Artigo Científico
• Fonte: Materials Research Bulletin; v. 164, p. 8-pg., 2023-04-05.

Resumo

Defects at semiconductors with electron acceptor and donor sites govern the electronic and optoelectronic ap-plications due to their unique electronic properties. This work provides deep insight into the nature of defects and the conduction mechanism in alpha-Ag2WO4. To this aim, a detailed analysis of the results of XRD with Rietveld refinements, FE-SEM images, and measurements of different spectroscopies (impedance, positron annihilation lifetime, and photoluminescence) are carried out on alpha-Ag2WO4 samples synthesized by a simple co-precipitation method. Two types of vacancy defects: cationic O-vacancies, and anionic Ag or Ag-O vacancy complexes are elucidated with a Schottky p-type potential barrier. The results indicate that the Ag vacancies remain constant during thermal treatment, while an opposite effect is found for the oxygen vacancies. This behavior governs the multifunctional properties of alpha-Ag2WO4 semiconductors via a tunneling plus thermionic conduction mechanism. (AU)

• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 19/01732-1 - Atividade fotocatalítica de semicondutores multifuncionais: influência da morfologia e injeção de elétrons
• Beneficiário: Amanda Fernandes Gouveia
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado