Controlled Al 3+ Incorporation in the ZnO Lattice at 188 °C by Soft Reactive Co-Sputtering for Transparent Conductive Oxides

Salvatore Sanzaro, Antonino La Magna, Emanuele Smecca, Giovanni Mannino, Giovanna Pellegrino, Enza Fazio, Fortunato Neri and Alessandra Alberti
Additional contact information
Salvatore Sanzaro: Department of Mathematical and Computational Sciences, Physics and Earth Sciences, University of Messina, V. le F. Stagno d’Alcontres 31, Messina 98166, Italy
Antonino La Magna: National Research Council-Institute for Microelectronics and Microsystems (CNR-IMM), Zona industriale Strada VIII n°5, Catania 95121, Italy
Emanuele Smecca: National Research Council-Institute for Microelectronics and Microsystems (CNR-IMM), Zona industriale Strada VIII n°5, Catania 95121, Italy
Giovanni Mannino: National Research Council-Institute for Microelectronics and Microsystems (CNR-IMM), Zona industriale Strada VIII n°5, Catania 95121, Italy
Giovanna Pellegrino: National Research Council-Institute for Microelectronics and Microsystems (CNR-IMM), Zona industriale Strada VIII n°5, Catania 95121, Italy
Enza Fazio: Department of Mathematical and Computational Sciences, Physics and Earth Sciences, University of Messina, V. le F. Stagno d’Alcontres 31, Messina 98166, Italy
Fortunato Neri: Department of Mathematical and Computational Sciences, Physics and Earth Sciences, University of Messina, V. le F. Stagno d’Alcontres 31, Messina 98166, Italy
Alessandra Alberti: National Research Council-Institute for Microelectronics and Microsystems (CNR-IMM), Zona industriale Strada VIII n°5, Catania 95121, Italy

Energies, 2016, vol. 9, issue 6, 1-13

Abstract: Transparent conductive oxide (TCO) layers, to be implemented in photo-anodes for dye-sensitized solar cells (DSCs), were prepared by co-deposition of ZnO and Al using pulsed-direct current (DC)-magnetron reactive sputtering processes. The films were deposited at low deposition temperatures (R T -188 °C) and at fixed working pressure (1.4 Pa) using soft power loading conditions to avoid intrinsic extra-heating. To compensate the layer stoichiometry, O 2 was selectively injected close to the sample in a small percentage (Ar:O 2 = 69 sccm:2 sccm). We expressly applied the deposition temperature as a controlling parameter to tune the incorporation of the Al 3+ species in the targeted position inside the ZnO lattice. With this method, Aluminum-doped Zinc Oxide films (ZnO:Al) were grown following the typical wurtzite structure, as demonstrated by X-ray Diffraction analyses. A combination of micro-Raman, X-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE) analyses has shown that the incorporated host-atoms are Al 3+ species in Zn 2+ substitutional position; their amount increases following a direct monotonic trend with the deposition temperature. Correspondently, the c-axis strain into the layer decreases due to the progressive ordering of the lattice structure and reducing clustering phenomena. The maximum average Al content inside the film was ~2%, as measured by energy dispersive X-ray (EDX) spectroscopy, with a uniform distribution of the dopant species along the layer thickness traced by depth-profile XPS analyses. The optimised ZnO:Al layer, deposited at a rate of ~7 nm/min, exhibits high transmittance in the visible range (~85%) and low resistivity values (~13 mΩ × cm). The material therefore fulfils all the requirements to be candidate as TCO for low-cost DSCs on flexible substrates for large area technologies.

Keywords: transparent conductive oxide (TCO); dye-sensitized solar cells (DSCs); Al doped ZnO (AZO); co-sputtering; doping; low temperature (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2016
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1996-1073/9/6/433/pdf (application/pdf)
https://www.mdpi.com/1996-1073/9/6/433/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:9:y:2016:i:6:p:433-:d:71363

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().