Download or read book Silicon Nanocrystals in Various Dielectric Matrices: Structural and Optical Properties written by Anastasiya Zelenina and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Zusammenfassung: AbstractThis dissertation is focused on the fundamental investigation of Si nanocrystals formed in annealed Si rich/stoichiometric dielectric multilayered structures. The films are prepared by size-controlled superlattices approach previously widely applied to SiOx/SiO2 superlattices. While a deep understanding of fundamental properties of Si nanocrystals in SiOx matrix has been already achieved, most of the results published on silicon nanocrystals in SiNx do not represent a clear understanding and sometimes even contradict to each other.Thereby, a starting point of the present research is a detailed study of Si nanocrystals embedded in Si nitride matrix. A careful development of plasma-enhanced chemical vapor deposition parameters allowed the deposition of optimized SiNx/Si3N4 superlattices of various SiNx thicknesses, which were further annealed in order to form Si nanocrystals of various sizes. Based on transmission electron microscopy and X-ray diffraction analysis, the formation of size-controlled Si nanocrystals of various sizes is confirmed. Despite photoluminescence spectra of these samples demonstrate the expected PL blue shift with the decrease of Si nanocrystal size, the shift is confirmed to be an optical artifact. The results presented here can explain a disagreement of the recent reports published on Si nanocrystals in SiNx matrix by other groups, as the photoluminescence peak shift is sometimes wrongly interpreted as nanocrystal size effect. Additionally, according to the concluded issues, novel hetero-combinations, which contain both silicon nitride and silicon oxide sublayers are proposed and realized. Although SiNx/SiO2 and SiOxNy/Si3N4 hetero-structures might show some benefits in optical and electrical properties compared to the standard SiOx/SiO2 and SiNx/Si3N4 superlattices, they have been only very barely studied previously. In the present work it is shown that high-temperature annealing leads to the destruction of SiNx/SiO2 hetero-superlattice, and Si nanocrystals of uncontrollable sizes irregularly distributed within the film are formed. At the same time SiOxNy/Si3N4 hetero-structure sustains high-temperature annealing and size-controlled Si nanocrystals demonstrate quantum luminescence