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- da Silva, A. Ferreira, et al.
(author)
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Growth, Electrical and Optical Properties of SnO2:F on ZnO, Si and Porous Si Structures
- 2009
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In: NANOTECH CONFERENCE & EXPO 2009, VOL 1, TECHNICAL PROCEEDINGS. - : CRC PRESS-TAYLOR & FRANCIS GROUP. - 9781439817827 ; , s. 352-
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Conference paper (peer-reviewed)abstract
- In this work we have analyzed the optical absorption of the ZnO and SnO2:F (FTO) films and applied them in porous silicon light-emitting diodes. The absorption and energy gap were calculated by employing the projector augmented wave method [1] within the local density approximation and with a modeled on-site self-interaction-like correction potential within the LDA+U-S/C [2]. Experiment and theory show a good agreement when the optical absorption and optical energy gap are considered. A layer of FTO is deposited by spray pyrolysis on top of porous Si (PSi) or ZnO/(PSi) in order to make the LEDs. The morphology and roughness of the films are analyzed by Atomic Force Microscopy before and after the FTO deposition. The electrical and optical properties are studied by characteristics curves J x V, and electroluminescence intensity versus bias.
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| 3. |
- Castro Meira, M. V., et al.
(author)
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Optical characterization of ZnO nanopillars on Si and macroporous periodic Si structure
- 2012
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 111:12, s. 123527-
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Journal article (peer-reviewed)abstract
- ZnO nanopillars were successfully grown using both the vapor-liquid-solid and the aqueous chemical growth methods on different substrates, such as quartz, n-, and p-type non-porous Si wafer (flat) and microporous periodic Si structure (MPSiS). Scanning electron microscopy was employed to compare sample morphologies. The absorption was calculated employing the GW(0) method, based on the local density approximation, and with the projector augmented wave approach. Experiment and theory show a reasonable agreement when the shape of the optical absorption is considered. The measured absorption of ZnO nanopillars, on different substrates, is lower than that observed for ZnO films on quartz substrate, in the energy gap spectral range. A strong effect of MPSiS substrates on ZnO nanopillar properties is observed. The photoluminescence technique was also employed as an optical characterization.
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| 5. |
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| 6. |
- Ferreira da Silva, Antonio, et al.
(author)
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Growth, Optical Characterization and Modelling of ZnO Nanorods on Si, SiC and Macroporous Si Structure
- 2009
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In: Nanotech 2009 Vol. 3Nanotechnology 2009: Biofuels, Renewable Energy, Coatings, Fluidics and Compact Modeling. - Austin, TX, USA : Nano Science and Technology Institute. - 9781439817841 ; , s. 206-209
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Conference paper (other academic/artistic)abstract
- Zinc Oxide (ZnO) and 4H-SiC are prominent materials with large applicability such as optoelectronic nanodevices and for instance ultraviolet detectors. There is lack of more information about optical transitions beyond the indirect band gap energy (BGE) of 4H-SiC and even more for ZnO direct BGE grown on the former material. Using the vapor-liquid-solid and the aqueous chemical growth methods we have grown ZnO nanorods on different substrates, such as quartz, n- and p-type silicon porous silicon and n-type 4H-SiC. The Scanning electron microscopy (SEM) are shown and compared for all samples. We have calculated the absorption and energy gap by employing a first-principle and a full-potential linearized augmented plane-wave (FPLAPW) method within the local density approximation (LDA). The absorption of ZnO nanorods, on different substrates, is lower than that of quartz substrate when photon energy is low. It is shown the strong effect of 4H-SiC on ZnO nanorods. Experiment and theory show a good aggreement when the optical energy gap is considered for both materials.
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