Si-rich Al 2 O 3 films grown by RF magnetron sputtering: structural and photoluminescence properties versus annealing tr
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NANO EXPRESS
Open Access
Si-rich Al2O3 films grown by RF magnetron sputtering: structural and photoluminescence properties versus annealing treatment Nadiia Korsunska1, Larysa Khomenkova1,2*, Oleksandr Kolomys1, Viktor Strelchuk1, Andrian Kuchuk1, Vasyl Kladko1, Tetyana Stara1, Oleksandr Oberemok1, Borys Romanyuk1, Philippe Marie2, Jedrzej Jedrzejewski3 and Isaac Balberg3
Abstract Silicon-rich Al2O3 films (Six(Al2O3)1−x) were co-sputtered from two separate silicon and alumina targets onto a long silicon oxide substrate. The effects of different annealing treatments on the structure and light emission of the films versus x were investigated by means of spectroscopic ellipsometry, X-ray diffraction, micro-Raman scattering, and micro-photoluminescence (PL) methods. The formation of amorphous Si clusters upon the deposition process was found for the films with x ≥ 0.38. The annealing treatment of the films at 1,050°C to 1,150°C results in formation of Si nanocrystallites (Si-ncs). It was observed that their size depends on the type of this treatment. The conventional annealing at 1,150°C for 30 min of the samples with x = 0.5 to 0.68 leads to the formation of Si-ncs with the mean size of about 14 nm, whereas rapid thermal annealing of similar samples at 1,050°C for 1 min showed the presence of Si-ncs with sizes of about 5 nm. Two main broad PL bands were observed in the 500- to 900-nm spectral range with peak positions at 575 to 600 nm and 700 to 750 nm accompanied by near-infrared tail. The low-temperature measurement revealed that the intensity of the main PL band did not change with cooling contrary to the behavior expected for quantum confined Si-ncs. Based on the analysis of PL spectrum, it is supposed that the near-infrared PL component originates from the exciton recombination in the Si-ncs. However, the most intense emission in the visible spectral range is due to either defects in matrix or electron states at the Si-nc/matrix interface. Keywords: Si-rich-Al2O3, Si nanocrystallites, Photoluminescence, XRD, Raman scattering
Background Silicon nanocrystallites (Si-ncs) attract considerable interest due to a significant transformation of optical and electrical properties in materials that contain them. These changes are caused by the quantum confinement effect [1-3]. Lightemitting Si-ncs embedded in dielectric hosts have potential applications in optoelectronic devices because of their compatibility with the existing manufacturing infrastructure for silicon integrated circuits. Among different dielectric materials, silicon oxide is the most addressed as a host for Si-ncs [4,5]. During the * Correspondence: [email protected] 1 V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky 03028, Kyiv, Ukraine 2 CIMAP (CEA/CNRS/Ensicaen/UCBN), 6 Boulevard Marechal Juin 14050, Caen, France Full list of author information is available at the end of the article
last decades, the properties of Si-nc-SiO2 systems have been widely investigated. Bright luminescence in a wide spectral range at room temperat
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