Нанокомпозити та наноматеріали

Nanocomposites based on (CaO-SiO2) and (2CaO-SiO2) on Silicon surface obtained by cavitation processing
R.K. Savkina, A.B. Smirnov
1 V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41 Nauky av, Kyiv 03028, Ukraine 
E-mail: rada.k.savkina@gmail.com

Functionalization of semiconductor substrates, specifically silicon, has focused attention toward such technological applications as photovoltaic and biosensing. Different chemical approaches have been employed for that usually. 
In this report, we focus on the alternative approach dealing with ultrasound-assisted modification of silicon. The purpose was to identify chemical functional groups and to evaluate bioactivity of the ultrasonically processed semiconductor. The properties of the Boron-doped p-type (100) silicon samples subjected to cavitation impacts have been studied. It was shown that high-intensity (15 W/cm2) and high-frequency (1 ÷ 6 MHz) sonication of silicon samples in the liquid nitrogen in a focused mode of acoustic action induces changes of the optical, chemical, and structural properties of semiconductor surface. 
The cavitation processing of the Si samples besides a structuring of semiconductor surface and possible phase transformation of bulk materials, results in formation of functional oxide layers consisted of such materials as SiO2, (CaO-SiO2) and (2CaO-SiO2). The formation of a new phase on the silicon surface is confirmed by the results of X-ray and µ-Raman spectroscopy investigations. The obtained composite structure has demonstrated photoluminescence in the (500-800 nm) spectral range. Bioactivity of the ultrasonically processed substrates was confirmed by the hydroxyapatite formation on the Si surface after storage in simulated body fluid solution.