{"title":"Microwave reflections for carrier lifetime measurements: a comprehensive study on sensitivity and transient response","authors":"Martin Schdfthaler, Rolf Brendel","doi":"10.1109/WCPEC.1994.520536","DOIUrl":"https://doi.org/10.1109/WCPEC.1994.520536","url":null,"abstract":"The time-resolved microwave reflection technique is widely used for process control in the photovoltaic community. We demonstrate how to optimize the sensitivity and the reliability of carrier lifetime measurements with this method. Our approach is based on a dielectric multilayer model that allows us to calculate microwave reflection transients from excess carrier decay after pulsed laser excitation. We find that the reflected microwave power mirrors the carrier decay only if the reflector is positioned appropriately.","PeriodicalId":20517,"journal":{"name":"Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC)","volume":"31 1","pages":"1656-1659 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1994-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85233860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Examination of optimized structures for a-Si:H based triple junction solar cells","authors":"S. Bae, S. Fonash","doi":"10.1109/WCPEC.1994.520003","DOIUrl":"https://doi.org/10.1109/WCPEC.1994.520003","url":null,"abstract":"We have examined a-Si:H based triple junction solar cells by using the AMPS computer program. We have found that, although the a-SiC:H material has wider band-gap, it does not yield better performance than a-Si:H absorber as the first absorber in the triple junctions because of the severely degraded material quality of today's a-SiC:H in the stabilized state. Moreover, for the stabilized state, we find that the optimized thickness distributions of a-Si:H based triple junctions are thinner than those determined in the annealed state. Our results for optimized stable efficiencies show that (1) with today's a-SiC:H materials, stabilized cell efficiencies can be better with a-Si:H top cells, (2) sub-cell layers need to be thinner than generation current matching would suggest, and (3) because of the need for thinner i-layers, the window losses become critical (to keep Jsc up).","PeriodicalId":20517,"journal":{"name":"Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC)","volume":"28 1","pages":"484-487 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1994-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85469872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Nagayoshi, M. Yamaguchi, Y. Yamamoto, M. Ikeda, T. Saitoh, K. Kamisako, T. Uematsu
{"title":"The effect of hydrogen-radical annealing for SiO/sub 2/ passivation","authors":"H. Nagayoshi, M. Yamaguchi, Y. Yamamoto, M. Ikeda, T. Saitoh, K. Kamisako, T. Uematsu","doi":"10.1109/WCPEC.1994.520500","DOIUrl":"https://doi.org/10.1109/WCPEC.1994.520500","url":null,"abstract":"The reduction of recombination velocity is important in obtaining high-efficiency solar cells, and SiO/sub 2/ passivation and hydrogen post-annealing are therefore widely used as surface passivation techniques. This investigation of hydrogen-radical post-annealing using the microwave hydrogen afterglow method shows that this procedure increases the effective lifetime of silicon wafers with SiO/sub 2/ passivation layers with a very short annealing time to a degree greater than does 3% H/sub 2/ forming gas annealing.","PeriodicalId":20517,"journal":{"name":"Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC)","volume":"242 1","pages":"1513-1514 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1994-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76771914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Ichikawa, T. Ihara, T. Hama, Y. Watanuki, S. Kato, H. Ota, H. Sakai, N. Sakai, J. Kurihara, O. Ishikawa
{"title":"A new flexible a-Si PV module and its application to rooftop PV systems","authors":"Y. Ichikawa, T. Ihara, T. Hama, Y. Watanuki, S. Kato, H. Ota, H. Sakai, N. Sakai, J. Kurihara, O. Ishikawa","doi":"10.1109/WCPEC.1994.520126","DOIUrl":"https://doi.org/10.1109/WCPEC.1994.520126","url":null,"abstract":"A novel photovoltaic (PV) module for roof top systems, solar roofing, is proposed. Solar roofing is a flexible amorphous silicon (a-Si) PV sheet having the function of roofing. Tempered glass is used as a roof covering material. Technical items for roof top systems using solar roofing are discussed. Preliminary studies on module component materials show the feasibility of solar roofing. The authors design a construction technology for tempered glass covered roofs and the effects of shadows on PV modules upon its performance are also analyzed.","PeriodicalId":20517,"journal":{"name":"Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC)","volume":"60 1","pages":"986-989 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1994-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83603771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"PV-modules at the facade of an inner courtyard-measurements and simulation","authors":"H.G. Groehn, H. Barthels","doi":"10.1109/WCPEC.1994.520133","DOIUrl":"https://doi.org/10.1109/WCPEC.1994.520133","url":null,"abstract":"For a PV generator installed at the facade of an inner courtyard, the irradiance losses due to shadowing have to be assessed and the PV modules must be connected in such away that the energy losses accumulated during the year are minimized. Besides direct radiation losses, the buildings surrounding the courtyard also cause a permanent reduction of the view factor, i.e. the sky section from which the modules receive light, which is different for every module of the facade. The influence of the diminished view factor on diffuse radiation under different irradiance conditions is calculated and validated by measurement. Profiles of the shadow, two different PV-module connection and the influence of a different number of bypass diodes on energy conversion are investigated.","PeriodicalId":20517,"journal":{"name":"Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC)","volume":"13 1","pages":"1016-1019 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1994-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84173505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Impurity and defect engineering approaches for realization of 18% commercial silicon solar cells","authors":"J. Benner, B. Sopori","doi":"10.1109/WCPEC.1994.520520","DOIUrl":"https://doi.org/10.1109/WCPEC.1994.520520","url":null,"abstract":"The Silicon Materials Program, managed by the National Renewable Energy Laboratory (NREL) for the US Department of Energy (DOE), emphasizes basic research issues in solar cell technologies that are critical to achieving 18% efficient commercial silicon solar cells in the near future. This program supports subcontracted research teams in topics of analysis of commercial silicon, clarification of the physics of point defect processes, and application of these processes in new device fabrication techniques. The program also includes in-house projects in crystal growth, investigation of advanced processes, materials characterization, and development of characterization techniques. In this paper, we provide an overview of significant results and indicate planned directions for future research in the program.","PeriodicalId":20517,"journal":{"name":"Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC)","volume":"7 3 1","pages":"1591-1594 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1994-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78265421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Contacts realization by rapid thermal annealing in multicrystalline silicon solar cells with special emphasis on metal influence","authors":"H. El omari, J. Boyeaux, A. Laugier","doi":"10.1109/WCPEC.1994.520507","DOIUrl":"https://doi.org/10.1109/WCPEC.1994.520507","url":null,"abstract":"To improve the quality of solar cell screen printed contacts, the authors have previously shown the capability to sinter the screen printed contacts by rapid thermal annealing (RTA) instead of commercial sintering; they have also noticed that the commonly used TiO/sub 2/ coating deposited by spray enhances the quality of the contact either with classical annealing or RTA. The aim of the present work is to analyse the metal influence on either front or back contacts realization by RTA on Polix p type multicrystalline silicon subsequently phosphorus diffused. The screen printed contact was replaced by the chosen metal dot obtained by evaporation. The authors have studied: Al/TiO/sub 2/; Ag/Al/TiO/sub 2/; Cu/Al/TiO/sub 2/; Pt/Al/TiO/sub 2/ and Cu/Cr/TiO/sub 2/. The RTA treatments were carried out at various temperatures and annealing time in an Ar ambience. The quality of the contacts are analysed from I-V characteristics, and possible diffusions of metallic species are characterized by SIMS experiments.","PeriodicalId":20517,"journal":{"name":"Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC)","volume":"150 1","pages":"1539-1542 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1994-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78514165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Thumm, A. Finke, B. Neumeier, B. Beck, A. Kettrup, H. Steinberger, P. Moskowitz
{"title":"Environmental and health aspects of CIS-module production, use and disposal","authors":"W. Thumm, A. Finke, B. Neumeier, B. Beck, A. Kettrup, H. Steinberger, P. Moskowitz","doi":"10.1109/WCPEC.1994.519858","DOIUrl":"https://doi.org/10.1109/WCPEC.1994.519858","url":null,"abstract":"Copper indium diselenide (CIS) is one of the most promising compounds in thin film technology. Since there is scant information available about environmental and health hazards, a study was initiated to characterize risks associated with the production, use and disposal of thin film photovoltaic modules. Data available from literature and developers of this technology contribute to an assessment of potential risks during production. In laboratory experiments the release of hazardous materials during operation caused by accidents or false handling and after disposal are simulated. In biological experiments the possible impact on living matter is established. These experiments comprise toxicity tests with aquatic organisms and rats representing mammals.","PeriodicalId":20517,"journal":{"name":"Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC)","volume":"47 1","pages":"262-265 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1994-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78549548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"PV based systems, with wind, diesel or LPG genset backup, supplying small TV rebroadcast stations in Portugal","authors":"H. F. Ramos","doi":"10.1109/WCPEC.1994.520164","DOIUrl":"https://doi.org/10.1109/WCPEC.1994.520164","url":null,"abstract":"This paper describes the implementation of a program intended to introduce PV based hybrid power systems to supply electrical power to small size TV rebroadcast stations in Portugal. Reliability is a major concern to this type of application as well as economical and social constraints, so wind or diesel/LPG genset backup are used. This paper includes a description of the systems behaviour, comparison among these topologies and economical viability data from a user's viewpoint.","PeriodicalId":20517,"journal":{"name":"Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC)","volume":"105 1","pages":"1141-1144 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1994-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73115585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Baldus, A. Bett, U. Blieske, T. Duong, F. Lutz, C. Schetter, W. Wettling, O. Sulima
{"title":"GaAs one-sun and concentrator solar cells based on LPE-ER grown structures","authors":"A. Baldus, A. Bett, U. Blieske, T. Duong, F. Lutz, C. Schetter, W. Wettling, O. Sulima","doi":"10.1109/WCPEC.1994.520544","DOIUrl":"https://doi.org/10.1109/WCPEC.1994.520544","url":null,"abstract":"The liquid-phase epitaxy etchback regrowth (LPE-ER) technique was used to grow AlGaAs/GaAs heteroface and AlGaAs/Al/sub y/Ga/sub 1-y/As(0.1<y<0.3) heteroface solar cell structures. The influence of substrate position (vertical or horizontal) during the LPE-ER process was investigated. A model for the growth of the LPE-ER structure in vertical substrate position is proposed. The LPE-ER grown structures were used to fabricate one-sun and concentrator solar cells. Efficiencies of up to 22.4% (AM1.5G) were achieved for solar cells of 4 cm/sup 2/ area. For concentrator application an efficiency of 24.8% (AM1.5, direct) was measured at 105 suns on a 13 mm/sup 2/ solar cell. A 243 cm/sup 2/ aperture area concentrator module consisting of 12 Fresnel lenses and 12 LPE-ER grown GaAs solar cells showed an efficiency of 20.3% under outdoor conditions.","PeriodicalId":20517,"journal":{"name":"Proceedings of 1994 IEEE 1st World Conference on Photovoltaic Energy Conversion - WCPEC (A Joint Conference of PVSC, PVSEC and PSEC)","volume":"207 1","pages":"1697-1700 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1994-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73120283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}