Experimental and ab Initio Studies of Deep-Bulk Traps in Doped Rare-Earth Oxide Thick Films

Author(s)

Rocha, Leandro S. R. ^[1] ; Schipani, Federico ^{[2, 3]} ; Aldao, Celso M. ^{[2, 3]} ; Cabral, Luis ^[4] ; Simoes, Alexandre Z. ^[5] ; Macchi, Carlos ^{[6, 7]} ; Marques, Gilmar E. ^{[4, 2, 3]} ; Ponce, Miguel A. ^{[1, 2, 3]} ; Longo, Elson ^[1]

Affiliation

^[1] Univ Fed Sao Carlos, Dept Chem, BR-13565905 Sao Carlos - Brazil

^[2] Univ Mar Del Plata, Inst Mat Sci & Technol INTEMA, RA-7600 Mar Del Plata - Argentina

^[3] Natl Res Council CONICET, RA-7600 Mar Del Plata - Argentina

^[4] Univ Fed Sao Carlos, Dept Phys, BR-13565905 Sao Carlos - Brazil

^[5] Sao Paulo State Univ UNESP, Sch Engn, BR-01049010 Guaratingueta - Brazil

^[6] Inst Fis Mat Tandil UNCPBA, RA-7000 Tandil - Argentina

^[7] Consejo Nacl Invest Cient & Tecn, CICPBA, UNCPBA, CIFICEN, RA-7000 Tandil - Argentina

• Document type: Journal article
• Source: Journal of Physical Chemistry C; v. 124, n. 1, p. 997-1007, JAN 9 2020.
• Web of Science Citations: 0

Abstract

Lanthanum-doped CeO2 is a promising semiconductor for gas sensing. A combined study applying impedance spectroscopy and first-principles calculations was performed for pure and lanthanum-doped samples. The results showed a strong influence of the localized Ce 4f states on the electrical conduction processes and an electrical resistance increase as a function of the exposure to vacuum and air atmospheres. After its modification with a rare-earth element along with exposure to reducing and oxidizing atmospheres, the observed behavior suggested the presence of multitraps, which depended on the described equilibrium between the oxygen vacancies (V-o(x) <-> V-O <-> V-O) in a disordered deep-bulk trap location. According to the DFT results, the multitraps were formed with the creation of an oxygen vacancy far from the doping atom. They were considered to be responsible for the phenomena modifying the Debye-like response. The transfer of electrons from Ce(III) to the adsorbed oxygen species, decreasing the number of electrons in the 4f state, reduced the electrical conductivity by the hopping frequency dependence of the total resistance and capacitances. This was probably due to the interactions between defective oxygen and metallic species. (AU)

• FAPESP's process: 18/20729-9 - Formation of Ag Nanoparticles by Laser Irradiation: An ab inicio Investigation
• Grantee: Luís Antônio Cabral
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 14/19142-2 - Characterization and processing of semiconductor nanostructures and application as devices
• Grantee: Gilmar Eugenio Marques
• Support type: Research Projects - Thematic Grants
• FAPESP's process: 18/20590-0 - NOVEL RENEWABLE RARE-EARTH BASED HYBRID NANOMATERIALS FOR ENVIRONMENTAL SENSING AND ENERGY-RELATED APPLICATIONS
• Grantee: Leandro Silva Rosa Rocha
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 16/25500-4 - Functionalization of semiconductor nanotubes via interfaces and gas adsorption: a computational approach
• Grantee: Naiara Letícia Marana
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 17/19143-7 - An experimental theoretical approach of conduction mechanisms and interface defects of heterostructures sensors based on p-n and n-n semiconductors from CeO2 matrices
• Grantee: Rafael Aparecido Ciola Amoresi
• Support type: Scholarships in Brazil - Post-Doctorate