Hall effect in printed Nanoparticulate Silicon Networks

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dc.contributor.advisorBritton, David Ten_ZA
dc.contributor.advisorHärting, Margiten_ZA
dc.contributor.authorGonfa, Girma Goroen_ZA
dc.date.accessioned2014-08-13T20:05:33Z
dc.date.available2014-08-13T20:05:33Z
dc.date.issued2010en_ZA
dc.description.abstractSilicon nanoparticles for the application of printed electronics were successfully synthesised and characterised. High energy milling has been proven to yield uncontaminated powder of median particle size 150 nm satisfying a lognormal distribution. Single crystalline P- and N-type silicon wafers, and metallurgical grade silicon were used as starting materials. The structural characterisation of all milled powders using X-ray diffraction (XRD), Small Angle X-ray Scattering (SAXS) and electron diffraction proved that the silicon nanoparticles are polycrystalline with a crystallite size of about 40 nm. For the first time, we have formulated printable semiconducting inks from nanoparticulate silicon. Silicon nanoparticles were mixed with organic binders, such as linseed oil and acrylic, to produce printable inks. Similarly nanoparticulate silicon ink, doped with inorganic salts, which is a different procedure to conventional impurity doping of the silicon structure, was produced with linseed oil. A home-built Hall measurement system was used to characterise layers of doped ink, for which a complete carrier type reversal was observed. Based on the result of elemental mapping, two possible models were suggested to explain the doping effect. A state-of-the-art Hall measurement system was used to perform field dependent analysis of screen printed silicon inks in van der Pauw geometry. A magnetoconductivity tensor model was developed to extract the carrier properties. All the layers were demonstrated to have at least two carrier types. Inks produced from P-type silicon maintained their carrier type, but reversal was observed for the N-type layers. The mobility of the carriers is better or comparable to similar classes of semiconducting materials. 2 More information on the interparticle connections were obtained from IV and impedance spectroscopy measurements which demonstrated the capacitive effects present in the printed layers. The capacitors originate at the interfaces between the metal and the layers and between the particles.en_ZA
dc.identifier.apacitationGonfa, G. G. (2010). <i>Hall effect in printed Nanoparticulate Silicon Networks</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Physics. Retrieved from http://hdl.handle.net/11427/6529en_ZA
dc.identifier.chicagocitationGonfa, Girma Goro. <i>"Hall effect in printed Nanoparticulate Silicon Networks."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Physics, 2010. http://hdl.handle.net/11427/6529en_ZA
dc.identifier.citationGonfa, G. 2010. Hall effect in printed Nanoparticulate Silicon Networks. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Gonfa, Girma Goro AB - Silicon nanoparticles for the application of printed electronics were successfully synthesised and characterised. High energy milling has been proven to yield uncontaminated powder of median particle size 150 nm satisfying a lognormal distribution. Single crystalline P- and N-type silicon wafers, and metallurgical grade silicon were used as starting materials. The structural characterisation of all milled powders using X-ray diffraction (XRD), Small Angle X-ray Scattering (SAXS) and electron diffraction proved that the silicon nanoparticles are polycrystalline with a crystallite size of about 40 nm. For the first time, we have formulated printable semiconducting inks from nanoparticulate silicon. Silicon nanoparticles were mixed with organic binders, such as linseed oil and acrylic, to produce printable inks. Similarly nanoparticulate silicon ink, doped with inorganic salts, which is a different procedure to conventional impurity doping of the silicon structure, was produced with linseed oil. A home-built Hall measurement system was used to characterise layers of doped ink, for which a complete carrier type reversal was observed. Based on the result of elemental mapping, two possible models were suggested to explain the doping effect. A state-of-the-art Hall measurement system was used to perform field dependent analysis of screen printed silicon inks in van der Pauw geometry. A magnetoconductivity tensor model was developed to extract the carrier properties. All the layers were demonstrated to have at least two carrier types. Inks produced from P-type silicon maintained their carrier type, but reversal was observed for the N-type layers. The mobility of the carriers is better or comparable to similar classes of semiconducting materials. 2 More information on the interparticle connections were obtained from IV and impedance spectroscopy measurements which demonstrated the capacitive effects present in the printed layers. The capacitors originate at the interfaces between the metal and the layers and between the particles. DA - 2010 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2010 T1 - Hall effect in printed Nanoparticulate Silicon Networks TI - Hall effect in printed Nanoparticulate Silicon Networks UR - http://hdl.handle.net/11427/6529 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/6529
dc.identifier.vancouvercitationGonfa GG. Hall effect in printed Nanoparticulate Silicon Networks. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Physics, 2010 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/6529en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Physicsen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherPhysicsen_ZA
dc.titleHall effect in printed Nanoparticulate Silicon Networksen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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