Open Access Nano Express

Si-rich Al2O3 films grown by RF magnetron sputtering: structural and photoluminescence properties versus annealing treatment

Nadiia Korsunska1, Larysa Khomenkova12*, Oleksandr Kolomys1, Viktor Strelchuk1, Andrian Kuchuk1, Vasyl Kladko1, Tetyana Stara1, Oleksandr Oberemok1, Borys Romanyuk1, Philippe Marie2, Jedrzej Jedrzejewski3 and Isaac Balberg3

Author Affiliations

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

3 Racah Institute of Physics, Hebrew University, 91904, Jerusalem, Israel

For all author emails, please log on.

Nanoscale Research Letters 2013, 8:273  doi:10.1186/1556-276X-8-273

Published: 7 June 2013

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