Effects of cobalt substitution on ZnO surface reactivity and electronic structure
| Autor: | Cinzia Di Giorgio, Aldo Amore Bonapasta, D. D'Agostino, Anna Maria Cucolo, Fabrizio Bobba, Paola Alippi, Antonio Di Trolio |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Band gap Fermi level chemistry.chemical_element 02 engineering and technology General Chemistry Electronic structure 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences 0104 chemical sciences Scanning probe microscopy symbols.namesake chemistry Impurity Phenomenological model Materials Chemistry symbols 0210 nano-technology Absorption (electromagnetic radiation) ZnO and Co:ZnO surface reactivity Cobalt |
| Zdroj: | JOURNAL OF MATERIALS CHEMISTRY C 7 (2019). doi:10.1039/c8tc06188b info:cnr-pdr/source/autori:Domenico D'Agostino, Cinzia Di Giorgio, Fabrizio Bobba, Antonio Di Trolio, Paola Alippi, Anna Maria Cucolo, Aldo Amore Bonapasta/titolo:Effects of cobalt substitution on ZnO surface reactivity and electronic structure/doi:10.1039%2Fc8tc06188b/rivista:JOURNAL OF MATERIALS CHEMISTRY C/anno:2019/pagina_da:/pagina_a:/intervallo_pagine:/volume:7 |
| ISSN: | 2050-7534 2050-7526 |
| DOI: | 10.1039/c8tc06188b |
| Popis: | We have performed scanning probe microscopy investigations of ZnO and Co-substituted ZnO under dark/UV conditions as well as in air and an ultra-high vacuum environment to shine a light on the change in electronic structure and surface reactivity as a consequence of Zn substitution with Co. We have achieved two major results: first, Co substituting Zn atoms significantly downward shifts by about 400 meV the Fermi level, which is close to the conduction band in the as-grown n-type ZnO. Second, a thoroughly novel result, Co substitution strongly reduces the absorption of negative oxygen species (NOS) at the ZnO surface. These two experimental findings are fully explained by a phenomenological model assuming the formation of Co-defect (Co-D) complexes that induce the appearance of an unoccupied impurity band in the ZnO energy gap. NOS play a central role in both the operating principles of UV photodetectors and applications in nanomedicine. Thus, the inhibiting effect of Co-D complexes on NOS formation has many applicative implications since it suggests that defect-engineering procedures might be devised for realizing nano-patterned Co-doped ZnO surfaces with regions showing different surface properties. |
| Databáze: | OpenAIRE |
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