StatusThe thesis was presented on the 11 March, 2019
Approved by NCAA on the 19 April, 2019
Abstract– 0.86 Mb / in romanian
3.69 Mb /
The structure of the thesis consists of introduction, 4 chapters, general conclusions, bi bliography of 107 titles, 100 pages of basic text, 78 figures and 10 tables. The results presented in the thesis were published in 24 scientific papers.
Field of research: Materials and structures for photovoltaics. Physics and Materials Technology.
The main goal of this work is to study the dependence of the photoelectric parameters of the ITO/n -Si, SiC/p-Si and Si3N4/p-Si structures on the state of their interface, finding techniques for controlling the interface state for the formation of a potential barrier that increases the solar cell conversion efficiency by elements on the basis of these structures.
Objectives of the study: - to improve the procedures for obtaining ITO/n-Si, SiC/p-Si and Si3N4/pSi junctions in order to obtain unilateral and bilateral sensitivity low-cost CS; - to develop a methodology for controlled the state of the interface structures in the process of their obtaining; -study of their electrical and photoelectric properties in order to establish a correlation between the technological conditions of preparation and the parameters of the devices obtained.
The novelty and scientific originality of the work are: - for the first time to obtain ITO/n-Si, SiC/p-Si and Si3N4/p-Si heterojunctions made by spray pyrolysis and HFNRMS methods, without using chemical etching of silicon; - in the development of methods for controlle the state of the interface of ITO/n-Si, SiC/p-Si and Si3N4/p-Si structures, which allows to obtain Schottky or SIStype structures with an inversion layer in the space charge region; - the manufacture of unilateral and bilateral functional samples of SCs based on ITO/n-Si heterostructures with a record conversion efficiency for these structures: 15.3% for unilateral and 14.15%/11.14% (front/back) for bilateral.
The solved scientific problem in the field of physics of semiconductor materials is to determine by studying the electrical, photoelectric, optical, structural, morphological and topological properties of the ITO/n-Si, SiC/p-Si and Si3N4/p-Si heterostructures for the manufacture of low-cost SCs with inversion layers and efficiency comparable to industrial models.
Theoretical significance: The physical processes which allow controlled interface formation of the ITO/n-Si, SiC/p-Si and Si3N4/p-Si heterostructure are determined. The practical significance of the work: - development of the installation and methods for obtaining heterojunctions ITO/n-Si, SiC/p-Si and Si3N4/p-Si; determination of technological conditions for obtaining ITO/n-Si, SiC/p-Si and Si3N4/p-Si heterojunctions with inversion layers; the development of an low-cost process for the fabrication of samples of solar cells based on ITO/n-Si, SiC/p-Si and Si3N4/p-Si heterostructures with the efficiency comparable to the efficiency of traditional devices.
Implementation of the results: The obtained scientific results can be implemented in the instructive-educational process at the Institute for Research and Innovation and the Faculty of Physics and Engineering of USM. The results presented in the current thesis were published in 24 scientific papers, 3 of which with impact factor. The researches were supported by the awarding of the Sergiu Rădăuţanu Nominal Scholarship (2016-2017) and the Scholarship World Excellence Exchange, Energy, 2016-2017.