Enhancement of optical and mechanical properties of Si nanopillars by ALD TiO2 coatingElectronic supplementary information (ESI) available. See DOI: 10.1039/c6ra21742g

• Main Authors: Pavlenko, M, Coy, E. L, Jancelewicz, M, Za ski, K, Smyntyna, V, Jurga, S, Iatsunskyi, I
• Format: Article
• Language: English
• ISSN: 2046-2069
• DOI: 10.1039/c6ra21742g

The mechanical and optical properties of Si and TiO 2 -Si nanopillars (NPl) were investigated. Mesoporous silicon NPl arrays were fabricated by metal-assisted chemical etching and nanosphere lithography, and then pillars were covered by TiO 2 using the atomic layer deposition technique. We performed scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, reflectance, photoluminescence (PL) spectroscopy and nanoindentation to characterize the as-prepared and annealed TiO 2 -Si NPl. The main structural and mechanical parameters of TiO 2 -Si NPl (grain size, strain, critical load, elastic recovery and Young's module) were calculated. Reflectance and PL spectroscopy were used to study the impact of morphology on optical properties of TiO 2 -Si NPl before and after annealing. It was established that the nanostructures of TiO 2 penetrated inside the porous matrix of Si pillar improve the mechanical properties of TiO 2 -Si NPl. The results of nanoindentation study have shown that Young's modulus of annealed TiO 2 -Si NPl is about three times higher than for the pure Si NPl. The mechanical and optical properties of Si and TiO 2 -Si nanopillars (NPl) were investigated.