{"id":{"repo_id":"njit","oai_identifier":"oai:digitalcommons.njit.edu:dissertations-1662"},"canonical_url":"https://search.dev.ndltd.org/etd/njit/oai:digitalcommons.njit.edu:dissertations-1662","repository":{"repo_id":"njit","name":"NJIT","base_url":"https://digitalcommons.njit.edu/do/oai/"},"display":{"title":"Fabrication and characterization of microcrystalline silicon solar cells","abstract":"In this study, single junction p-i-n uc-Si:H solar cells were prepared using plasma of silane diluted by hydrogen in a low-cost, single chamber, non-load-locked RF-PECVD system. Direct structural characterization of uc-Si:H solar cells, rather than stand-alone films, was conducted using Raman Spectroscopy, XRD, and AFM. Strong correlations among device deposition, i-layer structural properties, and device performance have been established. With such correlations, critical issues in fabricating low-cost, large-scale, high performance uc-Si:H solar cells were identified. The critical importance of seeding processes in determining the microstructure of uc-Si:H i-layers and performance of uc-Si:H solar cells has been demonstrated. Using p-layer seeding methods, stable conversion efficiencies of 5% have been achieved using very simple device configuration. Micro-crystallinity obtained from Raman scattering, presented as Ic/Ia, proved to be sensitive to the microstructure of uc-Si:H i-layers. Strong spatial non-uniformity of i-layer microstructure as well as variations in device performance were observed. A wide variety of i-layer microstructures, from mixed-phase Si:H to highly crystalline uc-Si:H, were revealed by Raman scattering. Generally, solar cells with mixed-phase Si:H i-layers exhibit high open circuit voltages, low fill factors, low efficiencies, and severe light-induced degradation. On the other hand, solar cells with truly uc-Si:H i-layers show low open circuit voltages, high fill factors, high efficiencies, and excellent stability against light-induced degradation. It was shown by XRD experiments that high performance, optimum uc-Si:H solar cells exhibit smaller grain sizes compared to solar cells with i-layers showing higher micro-crystallinity. Correlations among non-uniformity pattern, i-layer micro-crystallinity, and AFM surface morphologies were also observed. Solar cells with truly uc-Si:H i-layers exhibit excellent stability under both conventional and accelerated light soaking. Mixed-phase Si:H solar cells show much worse stability against light exposure. However, it has been demonstrated that stable, high performance uc-Si:H solar cells can only be obtained with i-layers being uc-Si:H, yet close to the uc-Si:H to mixed-phase Si:H transition edge where an optimum microcrystallinity range (Ic/Ia at around 1.8) was identified. These optimum uc-Si:H solar cells exhibit moderate open circuit voltages at 0.5 V, high fill factors, high efficiencies, and excellent stability against light-induced degradation. Such optimum uc-Si:H i-layers demand a very narrow optimum processing window.","abstract_html":"In this study, single junction p-i-n uc-Si:H solar cells were prepared using plasma of silane diluted by hydrogen in a low-cost, single chamber, non-load-locked RF-PECVD system. Direct structural characterization of uc-Si:H solar cells, rather than stand-alone films, was conducted using Raman Spectroscopy, XRD, and AFM. Strong correlations among device deposition, i-layer structural properties, and device performance have been established. With such correlations, critical issues in fabricating low-cost, large-scale, high performance uc-Si:H solar cells were identified. The critical importance of seeding processes in determining the microstructure of uc-Si:H i-layers and performance of uc-Si:H solar cells has been demonstrated. Using p-layer seeding methods, stable conversion efficiencies of 5% have been achieved using very simple device configuration. Micro-crystallinity obtained from Raman scattering, presented as Ic/Ia, proved to be sensitive to the microstructure of uc-Si:H i-layers. Strong spatial non-uniformity of i-layer microstructure as well as variations in device performance were observed. A wide variety of i-layer microstructures, from mixed-phase Si:H to highly crystalline uc-Si:H, were revealed by Raman scattering. Generally, solar cells with mixed-phase Si:H i-layers exhibit high open circuit voltages, low fill factors, low efficiencies, and severe light-induced degradation. On the other hand, solar cells with truly uc-Si:H i-layers show low open circuit voltages, high fill factors, high efficiencies, and excellent stability against light-induced degradation. It was shown by XRD experiments that high performance, optimum uc-Si:H solar cells exhibit smaller grain sizes compared to solar cells with i-layers showing higher micro-crystallinity. Correlations among non-uniformity pattern, i-layer micro-crystallinity, and AFM surface morphologies were also observed. Solar cells with truly uc-Si:H i-layers exhibit excellent stability under both conventional and accelerated light soaking. Mixed-phase Si:H solar cells show much worse stability against light exposure. However, it has been demonstrated that stable, high performance uc-Si:H solar cells can only be obtained with i-layers being uc-Si:H, yet close to the uc-Si:H to mixed-phase Si:H transition edge where an optimum microcrystallinity range (Ic/Ia at around 1.8) was identified. These optimum uc-Si:H solar cells exhibit moderate open circuit voltages at 0.5 V, high fill factors, high efficiencies, and excellent stability against light-induced degradation. Such optimum uc-Si:H i-layers demand a very narrow optimum processing window.","abstract_has_math":false,"creators":["Li, Liwei"],"institution":null,"degree_name":"Doctor of Philosophy in Materials Science and Engineering - (Ph.D.)","degree_level":null,"degree_discipline":"Committee for the Interdisciplinary Program in Materials Science and Engineering","degree_department":null,"school":null,"contributors":["Roland A. Levy","N. M. Ravindra","Marek Sosnowski"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2004,"date_issued":"2004-01-31T08:00:00Z","date_published":"2004-01-31T08:00:00Z","updated_at":"2026-07-24T03:22:52Z","subjects":["Microcrystalline silicon","Solar cell","Crystallinity","Amorphous silicon","Performance","Raman","Materials Science and Engineering"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.njit.edu/dissertations/607","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Roland A. Levy","N. M. Ravindra","Marek Sosnowski"]},{"key":"dc:creator","label":"Author","values":["Li, Liwei"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Committee for the Interdisciplinary Program in Materials Science and Engineering"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy in Materials Science and Engineering - (Ph.D.)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Microcrystalline silicon","Solar cell","Crystallinity","Amorphous silicon","Performance","Raman","Materials Science and Engineering"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.njit.edu/dissertations/607"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["In this study, single junction p-i-n uc-Si:H solar cells were prepared using plasma of silane diluted by hydrogen in a low-cost, single chamber, non-load-locked RF-PECVD system. Direct structural characterization of uc-Si:H solar cells, rather than stand-alone films, was conducted using Raman Spectroscopy, XRD, and AFM. Strong correlations among device deposition, i-layer structural properties, and device performance have been established. With such correlations, critical issues in fabricating low-cost, large-scale, high performance uc-Si:H solar cells were identified. The critical importance of seeding processes in determining the microstructure of uc-Si:H i-layers and performance of uc-Si:H solar cells has been demonstrated. Using p-layer seeding methods, stable conversion efficiencies of 5% have been achieved using very simple device configuration. Micro-crystallinity obtained from Raman scattering, presented as Ic/Ia, proved to be sensitive to the microstructure of uc-Si:H i-layers. Strong spatial non-uniformity of i-layer microstructure as well as variations in device performance were observed. A wide variety of i-layer microstructures, from mixed-phase Si:H to highly crystalline uc-Si:H, were revealed by Raman scattering. Generally, solar cells with mixed-phase Si:H i-layers exhibit high open circuit voltages, low fill factors, low efficiencies, and severe light-induced degradation. On the other hand, solar cells with truly uc-Si:H i-layers show low open circuit voltages, high fill factors, high efficiencies, and excellent stability against light-induced degradation. It was shown by XRD experiments that high performance, optimum uc-Si:H solar cells exhibit smaller grain sizes compared to solar cells with i-layers showing higher micro-crystallinity. Correlations among non-uniformity pattern, i-layer micro-crystallinity, and AFM surface morphologies were also observed. Solar cells with truly uc-Si:H i-layers exhibit excellent stability under both conventional and accelerated light soaking. Mixed-phase Si:H solar cells show much worse stability against light exposure. However, it has been demonstrated that stable, high performance uc-Si:H solar cells can only be obtained with i-layers being uc-Si:H, yet close to the uc-Si:H to mixed-phase Si:H transition edge where an optimum microcrystallinity range (Ic/Ia at around 1.8) was identified. These optimum uc-Si:H solar cells exhibit moderate open circuit voltages at 0.5 V, high fill factors, high efficiencies, and excellent stability against light-induced degradation. Such optimum uc-Si:H i-layers demand a very narrow optimum processing window."]},{"key":"dc:title","label":"Title","values":["Fabrication and characterization of microcrystalline silicon solar cells"]}]}],"canonical_facts":{"dc:contributor":["Roland A. Levy","N. M. Ravindra","Marek Sosnowski"],"dc:creator":["Li, Liwei"],"dc:description.abstract":["In this study, single junction p-i-n uc-Si:H solar cells were prepared using plasma of silane diluted by hydrogen in a low-cost, single chamber, non-load-locked RF-PECVD system. Direct structural characterization of uc-Si:H solar cells, rather than stand-alone films, was conducted using Raman Spectroscopy, XRD, and AFM. Strong correlations among device deposition, i-layer structural properties, and device performance have been established. With such correlations, critical issues in fabricating low-cost, large-scale, high performance uc-Si:H solar cells were identified. The critical importance of seeding processes in determining the microstructure of uc-Si:H i-layers and performance of uc-Si:H solar cells has been demonstrated. Using p-layer seeding methods, stable conversion efficiencies of 5% have been achieved using very simple device configuration. Micro-crystallinity obtained from Raman scattering, presented as Ic/Ia, proved to be sensitive to the microstructure of uc-Si:H i-layers. Strong spatial non-uniformity of i-layer microstructure as well as variations in device performance were observed. A wide variety of i-layer microstructures, from mixed-phase Si:H to highly crystalline uc-Si:H, were revealed by Raman scattering. Generally, solar cells with mixed-phase Si:H i-layers exhibit high open circuit voltages, low fill factors, low efficiencies, and severe light-induced degradation. On the other hand, solar cells with truly uc-Si:H i-layers show low open circuit voltages, high fill factors, high efficiencies, and excellent stability against light-induced degradation. It was shown by XRD experiments that high performance, optimum uc-Si:H solar cells exhibit smaller grain sizes compared to solar cells with i-layers showing higher micro-crystallinity. Correlations among non-uniformity pattern, i-layer micro-crystallinity, and AFM surface morphologies were also observed. Solar cells with truly uc-Si:H i-layers exhibit excellent stability under both conventional and accelerated light soaking. Mixed-phase Si:H solar cells show much worse stability against light exposure. However, it has been demonstrated that stable, high performance uc-Si:H solar cells can only be obtained with i-layers being uc-Si:H, yet close to the uc-Si:H to mixed-phase Si:H transition edge where an optimum microcrystallinity range (Ic/Ia at around 1.8) was identified. These optimum uc-Si:H solar cells exhibit moderate open circuit voltages at 0.5 V, high fill factors, high efficiencies, and excellent stability against light-induced degradation. Such optimum uc-Si:H i-layers demand a very narrow optimum processing window."],"dc:identifier":["https://digitalcommons.njit.edu/dissertations/607"],"dc:subject":["Microcrystalline silicon","Solar cell","Crystallinity","Amorphous silicon","Performance","Raman","Materials Science and Engineering"],"dc:title":["Fabrication and characterization of microcrystalline silicon solar cells"],"dc:type":["Dissertation"],"thesis:degree_discipline":["Committee for the Interdisciplinary Program in Materials Science and Engineering"],"thesis:degree_name":["Doctor of Philosophy in Materials Science and Engineering - (Ph.D.)"]},"updated_at":"2026-07-24T03:22:52Z"}