New Route for 'cold-Passivation' of Defects in Tin-Based Oxides
| Autor: | Monica Morales-Masis, Miglė Graužinytė, José A. Flores-Livas, Esteban Rucavado, Federica Landucci, Aïcha Hessler-Wyser, Yeonbae Lee, Takashi Koida, Quentin Jeangros, Christophe Ballif, Stefan Goedecker |
|---|---|
| Přispěvatelé: | Inorganic Materials Science |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Passivation Band gap Annealing (metallurgy) UT-Hybrid-D chemistry.chemical_element 02 engineering and technology 01 natural sciences chemistry.chemical_compound 0103 physical sciences Physical and Theoretical Chemistry 010302 applied physics business.industry Tin dioxide 021001 nanoscience & nanotechnology Surfaces Coatings and Films Electronic Optical and Magnetic Materials Amorphous solid General Energy chemistry 13. Climate action Density of states Optoelectronics Crystallite 0210 nano-technology business Tin |
| Zdroj: | Journal of physical chemistry C, 122(31), 17612-17620. American Chemical Society |
| ISSN: | 1932-7447 |
| Popis: | Transparent conductive oxides (TCOs) are essential in technologies coupling light and electricity. For Sn-based TCOs, oxygen deficiencies and undercoordinated Sn atoms result in an extended density of states below the conduction band edge. Although shallow states provide free carriers necessary for electrical conductivity, deeper states inside the band gap are detrimental to transparency. In zinc tin oxide (ZTO), the overall optoelectronic properties can be improved by defect passivation via annealing at high temperatures. Yet, the high thermal budget associated with such treatment is incompatible with many applications. Here, we demonstrate an alternative, low-temperature passivation method, which relies on cosputtering Sn-based TCOs with silicon dioxide (SiO 2). Using amorphous ZTO and amorphous/polycrystalline tin dioxide (SnO 2) as representative cases, we demonstrate through optoelectronic characterization and density functional theory simulations that the SiO 2 contribution is twofold. First, oxygen from SiO 2 passivates the oxygen deficiencies that form deep defects in SnO 2 and ZTO. Second, the ionization energy of the remaining deep defect centers is lowered by the presence of silicon atoms. Remarkably, we find that these ionized states do not contribute to sub-gap absorptance. This simple passivation scheme significantly improves the optical properties without affecting the electrical conductivity, hence overcoming the known transparency-conductivity trade-off in Sn-based TCOs. |
| Databáze: | OpenAIRE |
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