Fabrication of zinc oxide and nanostructured porous silicon composite micropatterns on silicon
Entity
UAM. Departamento de Física AplicadaPublisher
MDPIDate
2020-06-01Citation
10.3390/COATINGS10060529
Coatings 10.6 (2020): 529
ISSN
2079-6412 (online)DOI
10.3390/COATINGS10060529Funded by
This research was partially funded by Universidad Autónoma de Madrid, FPI-UAM grant (2019) and by the Egyptian Ministry of Higher Education, Missions Section under Egyptian Joint Supervision Grant, call 015/016Editor's Version
https://doi.org/10.3390/COATINGS10060529Subjects
Energy gap; Photoluminescence; ZnO; PSi; FísicaRights
© 2020 by the authorsAbstract
The luminescent properties of zinc oxide (ZnO) and nanostructured porous silicon (PSi)
make these materials very appealing for photoemission applications. The current study reports on
the fabrication of a composite of ZnO and nanostructured porous silicon micropatterns (ZnO + PSi
micropatterns) onto heavily-doped silicon surfaces. The proposed composite micropattern is devoted
to the future development of light-emitting diodes. The fabrication of the ZnO + PSi micropatterns
was carried out in a two–step process. (1) A regular hexagonal micropattern of a photoresist/ZnO
stack was fabricated by UV lithography on crystalline silicon substrates. (2) Before being lifted off
the photoresist, nanostructured PSi micropatterns were fabricated by electrochemically etching the
exposed areas of the silicon substrate. Subsequently, wet etching of the photoresist was carried out
for the final development of the composite ZnO and PSi micropatterns. Further, thin films of ZnO
and nanostructured PSi layers were characterized. In particular, their photoluminescent properties
were analyzed, as well as their morphology and composition. The experimental PL results show
that the ZnO layers have emission broadbands centered at (2.63 eV, blue), while the PSi layers show
a band centered at (1.71 eV, red). Further, the emission peaks from the PSi layers can be tuned by
changing their fabrication conditions. It was observed that the properties of the ZnO thin films are
not influenced by either the surface morphology of PSi or by its PL emissions. Therefore, the PL
properties of the composite ZnO + PSi micropatterns are equivalent to those featuring the addition of
PSi layers and ZnO thin films. Accordingly, broadband optical emissions are expected to arise from
a combination between the ZnO layer (blue band) and PSi (red band). Furthermore, the electrical
losses associated with the PSi areas can be greatly reduced since ZnO is in contact with the Si surface.
As a result, the proposed composite micropatterns might be attractive for many solid-state lighting
applications, such as light-emitting diodes
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Google Scholar:Ramadan Shehata Ali, Rehab
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Torres Costa, Vicente
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Martín-Palma, Raúl J.
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