Sonosynthesis of microstructures array for semiconductor photovoltaics

The properties of the 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 induces changes of the physical, chemical, and structural properties of semiconductor surface. Optical, atomic force and scanning electron microscopy techniques as well as energy dispersive X-ray spectroscopy, X-ray diffraction and photoresponse spectroscopy were used. The experimental study demonstrates the microstructure formation as well as a change of the chemical composition at the silicon surface. It was found that a significant rise in value and expansion of the spectral range of photosensitivity take place after cavitation treatment. The photoresponse of about 2.0 eV can be connected with the formation of Si-rich SiNx compound inside the ultrasonically structured region of Si. The obtained value of the refractive index confirms this assumption.