Pub Date : 2014-06-08DOI: 10.1109/PVSC.2014.6925362
Yusi Chen, Yangsen Kang, Y. Huo, D. Liang, Jieyang Jia, Li Zhao, Jeremy Kim, Leon Yao, J. Bregman, James S. Harris
Nanostructures have been widely used in solar cells due to their extraordinary optical management properties. However, due to the poor junction quality and large surface recombination velocity, typical nanostructured solar cells are not efficient. Here we demonstrate a new approach to design and fabricate whole-wafer nanostructures on dielectric layer for solar cell application. The design, simulation, fabrication and characterization of nanostructured dielectric layer silicon solar cells are presented. The optical simulation results illustrate that the periodic nanostructure array on dielectric materials suppresses the reflection and enhances the absorption over a wide spectral range. Reflection measurements show that reflection can be suppressed below 10% for a wide range of solar spectrum and incident angle. The current density-voltage (J-V) characterization shows that the short circuit current is improved by 44%. Our results suggest this nanostructured dielectric layer has the potential to significantly improve solar cell performance and avoid typical problems of defects and surface recombination for nanostructured solar cells, thus providing a new pathway towards realizing high-efficiency and low-cost solar cells.
{"title":"Nanostructured dielectric layer - A new approach to design nanostructured solar cells","authors":"Yusi Chen, Yangsen Kang, Y. Huo, D. Liang, Jieyang Jia, Li Zhao, Jeremy Kim, Leon Yao, J. Bregman, James S. Harris","doi":"10.1109/PVSC.2014.6925362","DOIUrl":"https://doi.org/10.1109/PVSC.2014.6925362","url":null,"abstract":"Nanostructures have been widely used in solar cells due to their extraordinary optical management properties. However, due to the poor junction quality and large surface recombination velocity, typical nanostructured solar cells are not efficient. Here we demonstrate a new approach to design and fabricate whole-wafer nanostructures on dielectric layer for solar cell application. The design, simulation, fabrication and characterization of nanostructured dielectric layer silicon solar cells are presented. The optical simulation results illustrate that the periodic nanostructure array on dielectric materials suppresses the reflection and enhances the absorption over a wide spectral range. Reflection measurements show that reflection can be suppressed below 10% for a wide range of solar spectrum and incident angle. The current density-voltage (J-V) characterization shows that the short circuit current is improved by 44%. Our results suggest this nanostructured dielectric layer has the potential to significantly improve solar cell performance and avoid typical problems of defects and surface recombination for nanostructured solar cells, thus providing a new pathway towards realizing high-efficiency and low-cost solar cells.","PeriodicalId":6649,"journal":{"name":"2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)","volume":"84 1","pages":"2202-2205"},"PeriodicalIF":0.0,"publicationDate":"2014-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83859313","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}
Pub Date : 2014-06-08DOI: 10.1109/PVSC.2014.6925289
B. Knisely, J. Kuitche, G. Tamizhmani, A. Korostyshevsky, H. Field
The purpose of this study is to accurately measure quantum efficiency of a single-junction crystalline silicon cell within a module using a non-intrusive methodology. This novel procedure for measuring the quantum efficiency for a specific location on a cell within a module will be referred to in this paper as cell-module quantum efficiency (C-M-QE). This paper will describe the equipment and conditions necessary to measure C-M-QE and discuss the factors that can influence this measurement. The ability to utilize a non-intrusive test to measure quantum efficiency of a cell within a module is extremely beneficial for reliability testing. Detailed methodologies for this innovative test procedure are not widely available in industry because equipment and measurement techniques have not been explored extensively. Results and conclusions provide the overall accuracy of the measurements and discuss the parameters affecting these measurements.
{"title":"Non-intrusive cell quantum efficiency measurements of accelerated stress tested photovoltaic modules","authors":"B. Knisely, J. Kuitche, G. Tamizhmani, A. Korostyshevsky, H. Field","doi":"10.1109/PVSC.2014.6925289","DOIUrl":"https://doi.org/10.1109/PVSC.2014.6925289","url":null,"abstract":"The purpose of this study is to accurately measure quantum efficiency of a single-junction crystalline silicon cell within a module using a non-intrusive methodology. This novel procedure for measuring the quantum efficiency for a specific location on a cell within a module will be referred to in this paper as cell-module quantum efficiency (C-M-QE). This paper will describe the equipment and conditions necessary to measure C-M-QE and discuss the factors that can influence this measurement. The ability to utilize a non-intrusive test to measure quantum efficiency of a cell within a module is extremely beneficial for reliability testing. Detailed methodologies for this innovative test procedure are not widely available in industry because equipment and measurement techniques have not been explored extensively. Results and conclusions provide the overall accuracy of the measurements and discuss the parameters affecting these measurements.","PeriodicalId":6649,"journal":{"name":"2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)","volume":"11 1","pages":"1870-1874"},"PeriodicalIF":0.0,"publicationDate":"2014-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83866991","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}
Pub Date : 2014-06-08DOI: 10.1109/PVSC.2014.6925349
S. Maximenko, M. Lumb, R. Hoheisel, M. González, D. Scheiman, S. Messenger, T. Tibbits, M. Imaizumi, T. Ohshima, S. Sato, P. Jenkins, R. Walters
In this paper, a complex analysis of the radiation response of GaAs solar cells with multi quantum wells (MQW) incorporated in the i-region of the device is presented. Electronic transport properties of the MQW i-region were assessed experimentally by the electron beam induced current (EBIC) technique. A 2-D EBIC diffusion model was applied to simulate EBIC line scans across device structure for different radiation doses. The results are interpreted using numerical modeling of the electrical field distribution at different radiation levels. Type conversion from n- to p-type was found in MQW i-region at displacement damage dose as low as low as ~9.88E9 MeV/g. This is supported by experimental and simulated EBIC and electric field distribution results.
{"title":"Effect of irradiation on gallium arsenide solar cells with multi quantum well structures","authors":"S. Maximenko, M. Lumb, R. Hoheisel, M. González, D. Scheiman, S. Messenger, T. Tibbits, M. Imaizumi, T. Ohshima, S. Sato, P. Jenkins, R. Walters","doi":"10.1109/PVSC.2014.6925349","DOIUrl":"https://doi.org/10.1109/PVSC.2014.6925349","url":null,"abstract":"In this paper, a complex analysis of the radiation response of GaAs solar cells with multi quantum wells (MQW) incorporated in the i-region of the device is presented. Electronic transport properties of the MQW i-region were assessed experimentally by the electron beam induced current (EBIC) technique. A 2-D EBIC diffusion model was applied to simulate EBIC line scans across device structure for different radiation doses. The results are interpreted using numerical modeling of the electrical field distribution at different radiation levels. Type conversion from n- to p-type was found in MQW i-region at displacement damage dose as low as low as ~9.88E9 MeV/g. This is supported by experimental and simulated EBIC and electric field distribution results.","PeriodicalId":6649,"journal":{"name":"2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)","volume":"85 1","pages":"2144-2148"},"PeriodicalIF":0.0,"publicationDate":"2014-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83903014","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}
Pub Date : 2014-06-08DOI: 10.1109/PVSC.2014.6925174
D. Scheiman, P. Jenkins, R. Walters, K. Trautz, R. Hoheisel, R. Tatavarti, R. Chan, H. Miyamoto, Jessica G. J. Adams, V. Elarde, C. Stender, A. Hains, C. McPheeters, C. Youtsey, N. Pan, M. Osowski
The Marines have increasing battery needs as fighting technology puts higher demands on the power they use. In an effort to offset this demand, the marines are investigating alternative energy sources, one being solar power. Mobile photovoltaics (PV) are a technology that can address these needs by leveraging flexible high efficiency III-V photovoltaic technology. The development of a lightweight, high efficiency solar panel to mount on, or stow in, a backpack and used to recharge a warfighters' battery was demonstrated. The panel consists of a 10 × 3 solar array of 20 cm2 epitaxial lift-off (ELO) Inverted Metamorphic (IMM) triple junction solar cells. In the first two phases of the project, single-junction GaAs cells with an efficiency of ~ 21% under AM1.5 illumination were used. Several of these systems were outfitted during Limited Objective Experiments (LOE) in February 2012 and August 2012. In the third and most current phase of this project, panels of triple-junction cells with an expected efficiency of 28-30% under AM1.5 illumination. Data from these LOEs are presented here. Although the panels are expensive, they have been demonstrated as a viable technology.
{"title":"High efficiency flexible triple junction solar panels","authors":"D. Scheiman, P. Jenkins, R. Walters, K. Trautz, R. Hoheisel, R. Tatavarti, R. Chan, H. Miyamoto, Jessica G. J. Adams, V. Elarde, C. Stender, A. Hains, C. McPheeters, C. Youtsey, N. Pan, M. Osowski","doi":"10.1109/PVSC.2014.6925174","DOIUrl":"https://doi.org/10.1109/PVSC.2014.6925174","url":null,"abstract":"The Marines have increasing battery needs as fighting technology puts higher demands on the power they use. In an effort to offset this demand, the marines are investigating alternative energy sources, one being solar power. Mobile photovoltaics (PV) are a technology that can address these needs by leveraging flexible high efficiency III-V photovoltaic technology. The development of a lightweight, high efficiency solar panel to mount on, or stow in, a backpack and used to recharge a warfighters' battery was demonstrated. The panel consists of a 10 × 3 solar array of 20 cm2 epitaxial lift-off (ELO) Inverted Metamorphic (IMM) triple junction solar cells. In the first two phases of the project, single-junction GaAs cells with an efficiency of ~ 21% under AM1.5 illumination were used. Several of these systems were outfitted during Limited Objective Experiments (LOE) in February 2012 and August 2012. In the third and most current phase of this project, panels of triple-junction cells with an expected efficiency of 28-30% under AM1.5 illumination. Data from these LOEs are presented here. Although the panels are expensive, they have been demonstrated as a viable technology.","PeriodicalId":6649,"journal":{"name":"2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)","volume":"43 1","pages":"1376-1380"},"PeriodicalIF":0.0,"publicationDate":"2014-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86640733","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}
Pub Date : 2014-06-08DOI: 10.1109/PVSC.2014.6924908
Wenpeng Deng, G. Amaratunga
In Photovoltaic (PV) energy systems, Maximum Power Point Tracking (MPPT) is essential in order to efficiently use the solar energy converted. There are many MPPT algorithms. Incremental Conductance (IncCond) is a popular algorithm which is widely used for rapidly changing atmospheric conditions. It is shown that it has no significant increase in convergence speed compared with the most popular empirically based Perturb and Observe (P&O) methods. In this paper, an alternative is proposed to track the MPP under rapidly changing atmospheric and partial shading conditions. In response to a sudden change in radiation from 100% to 30%, this method can converge to the MPP in 20ms. This is the fastest convergence time reported to date, which also has the capability of finding the global peak under partial shading conditions. The ultimate limit of how fast any MPPT algorithm can converge is also discussed.
{"title":"Limits of Incremental Conductance for determining the Maximum Power Point under rapidly changing irradiance and an alternative technique based on fast scanning","authors":"Wenpeng Deng, G. Amaratunga","doi":"10.1109/PVSC.2014.6924908","DOIUrl":"https://doi.org/10.1109/PVSC.2014.6924908","url":null,"abstract":"In Photovoltaic (PV) energy systems, Maximum Power Point Tracking (MPPT) is essential in order to efficiently use the solar energy converted. There are many MPPT algorithms. Incremental Conductance (IncCond) is a popular algorithm which is widely used for rapidly changing atmospheric conditions. It is shown that it has no significant increase in convergence speed compared with the most popular empirically based Perturb and Observe (P&O) methods. In this paper, an alternative is proposed to track the MPP under rapidly changing atmospheric and partial shading conditions. In response to a sudden change in radiation from 100% to 30%, this method can converge to the MPP in 20ms. This is the fastest convergence time reported to date, which also has the capability of finding the global peak under partial shading conditions. The ultimate limit of how fast any MPPT algorithm can converge is also discussed.","PeriodicalId":6649,"journal":{"name":"2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)","volume":"12 1","pages":"3690-3694"},"PeriodicalIF":0.0,"publicationDate":"2014-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86759093","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}
Pub Date : 2014-06-08DOI: 10.1109/PVSC.2014.6925227
S. Dhage, P. Chandrasekhar, S. Chandrasekhar, S. Joshi
Non-vacuum processes are of great interest for development of low-cost chalcopyrite-based photovoltaic technologies. Apart from the expensive vacuum-based routes that are widely adopted, another negative feature of the popularly employed methods is the need for selenization treatment, which significantly impacts the microstructure of the absorber layer and, in turn, also determines the performance of the device. A novel process for preparation of Cu(In0.7Ga0.3)Se2 (CIGS) films from an ink constituted of CIGS nanoparticles utilizing a convenient intense pulsed light (IPL) treatment is investigated in the present study. Initially, a thorough optimization of ink formulation variables was carried out in order to make the CIGS ink suitable for ink jet printing. The home-made CIGS ink, comprising CIGS nanoparticles with appropriate additives, was then successfully deposited with a print head having 256 nozzles on Mo coated soda lime glass substrate. Subsequently, IPL was used to treat the printed CIGS ink. Post IPL treatment, a CIGS film retaining the chalcopyrite structure even after melting and recrystallization, with no secondary phase formation, was realized. The phase constitution, thickness and morphology of prepared films were determined using X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF) and field emission scanning electron microscopy (FESEM). The above non-vacuum, room temperature process not requiring any selenization treatment can have important implications in realization of cost-effective CIGS absorber layers.
{"title":"CIGS absorber layer by single-step non-vacuum intense pulsed light treatment of inkjet-printed film","authors":"S. Dhage, P. Chandrasekhar, S. Chandrasekhar, S. Joshi","doi":"10.1109/PVSC.2014.6925227","DOIUrl":"https://doi.org/10.1109/PVSC.2014.6925227","url":null,"abstract":"Non-vacuum processes are of great interest for development of low-cost chalcopyrite-based photovoltaic technologies. Apart from the expensive vacuum-based routes that are widely adopted, another negative feature of the popularly employed methods is the need for selenization treatment, which significantly impacts the microstructure of the absorber layer and, in turn, also determines the performance of the device. A novel process for preparation of Cu(In0.7Ga0.3)Se2 (CIGS) films from an ink constituted of CIGS nanoparticles utilizing a convenient intense pulsed light (IPL) treatment is investigated in the present study. Initially, a thorough optimization of ink formulation variables was carried out in order to make the CIGS ink suitable for ink jet printing. The home-made CIGS ink, comprising CIGS nanoparticles with appropriate additives, was then successfully deposited with a print head having 256 nozzles on Mo coated soda lime glass substrate. Subsequently, IPL was used to treat the printed CIGS ink. Post IPL treatment, a CIGS film retaining the chalcopyrite structure even after melting and recrystallization, with no secondary phase formation, was realized. The phase constitution, thickness and morphology of prepared films were determined using X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF) and field emission scanning electron microscopy (FESEM). The above non-vacuum, room temperature process not requiring any selenization treatment can have important implications in realization of cost-effective CIGS absorber layers.","PeriodicalId":6649,"journal":{"name":"2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)","volume":"21 1","pages":"1607-1610"},"PeriodicalIF":0.0,"publicationDate":"2014-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89057528","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}
Pub Date : 2014-06-08DOI: 10.1109/PVSC.2014.6924995
V. Kuznetsov, M. Ernst, E. Granneman
Surface passivation is of vital importance for next generation solar cells. Outstanding properties of atomic layer deposition (ALD) can be employed to passivate Si surface with very good uniformity over large areas, excellent step coverage on non-planar surfaces and precise thickness control of nano-thick layers. The challenge is to apply ALD in a cost effective way acceptable for PV industry. In this work we report on the development of atmospheric pressure spatial ALD for (inline) deposition of Al2O3 layers with a throughput of 2000-3600 wafers/hour and low TMA precursor consumption. Layers with a thickness of 6-10 nm are optimal for rear side passivation, resulting in effective chemical and field-effect passivation without delamination (blistering) at the contact annealing step. This passivation is implemented in mass production and gives an efficiency improvement of 0.4-0.8% for PERC type solar cells.
{"title":"Al2O3 surface passivation of silicon solar cells by low cost ald technology","authors":"V. Kuznetsov, M. Ernst, E. Granneman","doi":"10.1109/PVSC.2014.6924995","DOIUrl":"https://doi.org/10.1109/PVSC.2014.6924995","url":null,"abstract":"Surface passivation is of vital importance for next generation solar cells. Outstanding properties of atomic layer deposition (ALD) can be employed to passivate Si surface with very good uniformity over large areas, excellent step coverage on non-planar surfaces and precise thickness control of nano-thick layers. The challenge is to apply ALD in a cost effective way acceptable for PV industry. In this work we report on the development of atmospheric pressure spatial ALD for (inline) deposition of Al2O3 layers with a throughput of 2000-3600 wafers/hour and low TMA precursor consumption. Layers with a thickness of 6-10 nm are optimal for rear side passivation, resulting in effective chemical and field-effect passivation without delamination (blistering) at the contact annealing step. This passivation is implemented in mass production and gives an efficiency improvement of 0.4-0.8% for PERC type solar cells.","PeriodicalId":6649,"journal":{"name":"2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)","volume":"1 1","pages":"0608-0611"},"PeriodicalIF":0.0,"publicationDate":"2014-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83261215","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}
Pub Date : 2014-06-08DOI: 10.1109/PVSC.2014.6924964
A. Licht, Dante F. DeMeo, J. B. Rodriguez, T. Vandervelde
At present, the state of the art thermophotovoltaic diode material is GaSb, with a bandgap of 0.7 eV corresponding to source temperatures greater than 1000°C. We investigate alternative bandstructure designs using the InAs/GaSb superlattice material system, which enable shorter bandgaps corresponding to lower source temperatures. For an InAs/GaSb superlattice system, we examine the effect of a monovalent barrier inserted between the p and n-doped regions. Through simulations, with the program Silvaco, we demonstrate that this barrier decreases the dark current and increases the open-circuit voltage, improving the overall power output and, thus, extending the operational wavelength of thermophotovoltaics.
{"title":"Decreasing dark current in long wavelength InAs/GaSb thermophotovoltaics via bandgap engineering","authors":"A. Licht, Dante F. DeMeo, J. B. Rodriguez, T. Vandervelde","doi":"10.1109/PVSC.2014.6924964","DOIUrl":"https://doi.org/10.1109/PVSC.2014.6924964","url":null,"abstract":"At present, the state of the art thermophotovoltaic diode material is GaSb, with a bandgap of 0.7 eV corresponding to source temperatures greater than 1000°C. We investigate alternative bandstructure designs using the InAs/GaSb superlattice material system, which enable shorter bandgaps corresponding to lower source temperatures. For an InAs/GaSb superlattice system, we examine the effect of a monovalent barrier inserted between the p and n-doped regions. Through simulations, with the program Silvaco, we demonstrate that this barrier decreases the dark current and increases the open-circuit voltage, improving the overall power output and, thus, extending the operational wavelength of thermophotovoltaics.","PeriodicalId":6649,"journal":{"name":"2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)","volume":"21 1","pages":"0482-0486"},"PeriodicalIF":0.0,"publicationDate":"2014-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83272619","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}
Pub Date : 2014-06-08DOI: 10.1109/PVSC.2014.6925297
Yasemin Kutes, J. Bosse, B. Aguirre, J. Cruz-Campa, J. Michael, D. Zubia, E. Spoerke, B. Huey
A new approach to measure the local response of micropatterned CdTe based solar cells is presented. This method provides fast results with high spatial resolution and the ability to map short circuit current (Ish), open circuit voltage (Voc), maximum power, and fill factor. It is based on consecutive photoconductive atomic force microscopy (pcAFM) scans collected at different DC biases over the same area. An array of I-V response curves results based on spectra for any given location (image pixel) according to the photoresponse (pcAFM current contrast) as a function of the applied bias (image). Grains, grain boundaries and even twin boundaries are clearly resolved.
{"title":"Nanoscale photovoltaic performance in micro/nanopatterned CdTe-CdS thin film solar cells","authors":"Yasemin Kutes, J. Bosse, B. Aguirre, J. Cruz-Campa, J. Michael, D. Zubia, E. Spoerke, B. Huey","doi":"10.1109/PVSC.2014.6925297","DOIUrl":"https://doi.org/10.1109/PVSC.2014.6925297","url":null,"abstract":"A new approach to measure the local response of micropatterned CdTe based solar cells is presented. This method provides fast results with high spatial resolution and the ability to map short circuit current (Ish), open circuit voltage (Voc), maximum power, and fill factor. It is based on consecutive photoconductive atomic force microscopy (pcAFM) scans collected at different DC biases over the same area. An array of I-V response curves results based on spectra for any given location (image pixel) according to the photoresponse (pcAFM current contrast) as a function of the applied bias (image). Grains, grain boundaries and even twin boundaries are clearly resolved.","PeriodicalId":6649,"journal":{"name":"2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)","volume":"57 1","pages":"1903-1907"},"PeriodicalIF":0.0,"publicationDate":"2014-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88706443","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}
Pub Date : 2014-06-08DOI: 10.1109/PVSC.2014.6925073
D. Meysing, M. Griffith, W. Rance, M. Reese, J. Burst, C. Wolden, T. Barnes
In this work, we report on the development of a reactive sputtering process for CdS:O for high efficiency CdTe solar cells. X-ray diffraction, UV-Vis-NIR spectrophotometry, and Rutherford backscattering spectrometry were used to characterize the crystal structure, composition, and optical properties, respectively. All films were slightly Cd-rich, while the bulk oxygen content increased up to 45 at. % in direct proportion to the O2 partial pressure. Optical absorption in cells was reduced by increasing the oxygen fraction in the sputtering ambient. Optimal performance was obtained from cells with CdS sputtered in a 6% O2/Ar ambient, yielding efficiency >14% and VOC >840 mV.
{"title":"Properties of oxygenated cadmium sulfide (CdS:O) and their impact on CdTe device performance","authors":"D. Meysing, M. Griffith, W. Rance, M. Reese, J. Burst, C. Wolden, T. Barnes","doi":"10.1109/PVSC.2014.6925073","DOIUrl":"https://doi.org/10.1109/PVSC.2014.6925073","url":null,"abstract":"In this work, we report on the development of a reactive sputtering process for CdS:O for high efficiency CdTe solar cells. X-ray diffraction, UV-Vis-NIR spectrophotometry, and Rutherford backscattering spectrometry were used to characterize the crystal structure, composition, and optical properties, respectively. All films were slightly Cd-rich, while the bulk oxygen content increased up to 45 at. % in direct proportion to the O2 partial pressure. Optical absorption in cells was reduced by increasing the oxygen fraction in the sputtering ambient. Optimal performance was obtained from cells with CdS sputtered in a 6% O2/Ar ambient, yielding efficiency >14% and VOC >840 mV.","PeriodicalId":6649,"journal":{"name":"2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)","volume":"18 1","pages":"0964-0967"},"PeriodicalIF":0.0,"publicationDate":"2014-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90627392","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}
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