**6. Conclusions**

The unique properties of fianite as monolithic substrute and buffer layer for Si, Ge and АIIIBV compounds epitaxy; protecting*,* stabilizing and antireflecting coatings, as well as a gate dielectric in photosensitive opto-electronic devices have been demonstrated. The results obtained in this work have actually demonstrated advantages of fianite as novel multipurpose material for new optoelectronics technologies.
