Formation of silicon nanocomposites by annealing of (SiOx/Sm)n multilayers: luminescence, Raman and FTIR studies

• Published in: Applied nanoscience 2023-11, Vol.13 (11), p.7187-7194
• Main Authors: Michailovska, Katerina V., Indutnyi, Ivan Z., Shepeliavyi, Petro E., Sopinskyy, Mykola V., Dan’ko, Viktor A., Tsybrii, Zinoviia F., Maziar, Denys M.
• Format: Article
• Language: English
• Subjects: Absorption spectra; Annealing; Chemistry and Materials Science; Comparative studies; Crystallization; Decomposition; Evaporation; Materials Science; Membrane Biology; Monolayers; Multilayers; Nanochemistry; Nanocomposites; Nanocrystals; Nanoparticles; Nanotechnology; Nanotechnology and Microengineering; Original Article; Raman spectra; Samarium; Silicon; Silicon dioxide; Stoichiometry; Transition temperature
• ISSN: 2190-5509; 2190-5517
• DOI: 10.1007/s13204-023-02887-2

A comparative study of the processes of metal-stimulated formation of silicon nanocrystals in SiO x –Sm structures was carried out. Samples with identical oxide matrix stoichiometry and Sm impurity content were formed using two methods: layer-by-layer deposition and coevaporation of SiO and Sm. Studies of PL and IR absorption spectra found that the admixture of samarium in samples of both types accelerates the thermally stimulated decomposition of samarium-doped SiO x films into Si and SiO 2 and reduces the transition temperature of silicon nanoparticles from an amorphous state to a crystalline state. However, in (SiO x /Sm) 10 multilayers, this effect is more pronounced than in single-layer films obtained using the co-evaporation method. Studying the Raman spectra of (SiO x /Sm) 10 multilayers annealed at 750 °C determined that the relative volume fraction of nanocrystals in the silicon phase of the sample is ~ 38%. No line corresponding to the crystalline nc-Si was observed in the Raman spectra of samples deposited by co-evaporation and annealed under the same conditions. For these samples, a narrow line in the Raman spectrum corresponding to crystalline nc-Si appears only after annealing at 970 °C. In this case, the relative fraction of Si nanocrystals in the silicon phase of the sample was ~ 17%, 2.2 times less than for a similar multilayer annealed at 750 °C. This also indicates that, in multilayer (SiO x /Sm) 10 samples, the thermally stimulated decomposition of SiO x , as well as the formation and crystallization of silicon nanoparticles, occurs at lower temperatures than in similar samples obtained by coevaporation. A possible mechanism for lowering the crystallization temperature of nc-Si in (SiO x /Sm) 10 multilayers is discussed.