Se denomina mono porque est formado por un cristal nico, disponiendo de una red cristalina continua. Moreover, the first trials of depositing heterojunction solar cells between p-type crystalline silicon and n-type polycrystalline silicon, gave encouraging results. El silicio cristalino se obtiene a travs de un proceso complejo que elimina las impurezas y permite obtener lminas finas y con bordes redondeados de una gran pureza. In conclusion, our results demonstrate the feasibility of depositing, by AP-CVD at intermediate temperatures, doped polycrystalline silicon films on glass substrates with interesting properties for photovoltaic applications. Meanwhile, Hall effect measurements show that the layers can be grown intrinsic, n-type or p-type depending on the dopant added. The dark conductivity measurements as a function of temperature show that films may be obtained with activation energies between 0.61 and 0.03 eV. On the other hand, the n-type samples lack of columnar structure or preferential orientation, which shows that phosphorus inhibits such growth regime. For p-type doped samples we observed a columnar structure appropriate for electrical conduction in photovoltaic cells, whereas X-ray diffraction reveals a strong (2 2 0) preferential orientation. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe the surface and cross section of the samples. El mono-Si también sirve como material fotovoltaico y absorbente de la luz en la fabricación de células solares. The films obtained are homogeneous and have good adhesion to the substrate. El silicio monocristalino es el material base para los chips de silicio que se utilizan en prácticamente todos los equipos electrónicos en la actualidad. We use as a substrate a commercial aluminosilicate float glass, which resists the deposition temperature of 850 ☌. The batch-type hot-wall CVD reactor uses SiHCl3 as precursor, H2 as carrier and reaction gas, BBr3 as p-type dopant, and PCl3 as n-type dopant. Structural characterizations are carried out mainly by (i) Scanning Electron Microscopy (SEM), (ii) Transmission Electron Microscopy (TEM), (iii) Fourier Transform Infra Red Spectrometry (FTIR) and other techniques.In this work we use atmospheric pressure chemical vapor deposition (AP-CVD) to deposit thin layers of polycrystalline silicon (poly-Si) on glass substrates. All these structures are fabricated by techniques derived from classic (i) Ion Beam Induced Crystallization (IBIC), (ii) Chemical Vapour Deposition (CVD) or (iii) Molecular Beam Epitaxy (MBE). This is the limit needed for the beginning of their industrial production and commercialization.Samples studied in this work are framed inside three groups: (1) Silicon Carbide and other phases (Silicon Nitride (Si3N4) and carbon nitride (C3N4)) synthesized by Silicon ion implantation, (2) Silicon Carbide synthesized by Si carbonisation and (3) Silicon Carbide and Gallium Nitride heteroepitaxial growth on carbonized Si. Therefore, long life are foreseen for electronic devices that could use these substrates. El producto de éste proceso es silicio policristalino ó poli-Si con nivel de pureza 99.999 (0.0001 ppm) o menor. Indeed, their use allow a significant reduction of the high defect density present in III-N or SiC alloys compared to their quality when directly grown on Si. These approaches let the consecution of a crystalline quality enough to the development of devices. The characterization of these structures allows to gather data and better physical and chemical understanding of these systems.The main objectives are (i) the fabrication and characterization of SiC and other interesting crystalline phases obtained from Si wafers and (ii) to demonstrate that these products are a viable way for using them as templates, compliant, seed or buffer layers in SiC or III-N overgrowth by epitaxial growth techniques. SiC is fabricated starting from single-crystalline silicon (Si) substrates by carbonization or by ion implantation. Mechanisms of formation involved in both thin films and crystalline precipitates of silicon carbide (SiC) are studied in this Ph.
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