Pub Date : 2011-06-19DOI: 10.1109/PVSC.2011.6186519
K. Macielak, M. Igalson, S. Spiering
The metastable behaviour induced by light soaking and reverse bias treatment in Cu(In, Ga)Se2 (CIGS) based solar cells with vapour deposited indium sulphide buffer layer is compared to the baseline CdS-buffered devices. The dark and light current-voltage characteristics, capacitance-voltage doping profiles and admittance spectra have been measured and the influence of light soaking and reverse bias treatment on these characteristics were investigated. While the changes induced by both treatments on charge distribution in the absorber in both types of cells were similar, only a minor impact on the photovoltaic parameters of In2S3-buffered cells was observed. Thus we conclude that In2S3 buffer is a good alternative to CdS in terms of ensuring a stable cell performance.
{"title":"Comparison of metastabilities in CIGS solar cells with In2S3 and CdS buffer layers","authors":"K. Macielak, M. Igalson, S. Spiering","doi":"10.1109/PVSC.2011.6186519","DOIUrl":"https://doi.org/10.1109/PVSC.2011.6186519","url":null,"abstract":"The metastable behaviour induced by light soaking and reverse bias treatment in Cu(In, Ga)Se2 (CIGS) based solar cells with vapour deposited indium sulphide buffer layer is compared to the baseline CdS-buffered devices. The dark and light current-voltage characteristics, capacitance-voltage doping profiles and admittance spectra have been measured and the influence of light soaking and reverse bias treatment on these characteristics were investigated. While the changes induced by both treatments on charge distribution in the absorber in both types of cells were similar, only a minor impact on the photovoltaic parameters of In2S3-buffered cells was observed. Thus we conclude that In2S3 buffer is a good alternative to CdS in terms of ensuring a stable cell performance.","PeriodicalId":373149,"journal":{"name":"2011 37th IEEE Photovoltaic Specialists Conference","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115509097","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 : 2011-06-19DOI: 10.1109/PVSC.2011.6186360
Pei-Hsuan Huang, Hsun-Wen Wang, M. Tsai, F. Lai, S. Kuo, H. Kuo, S. Chi
In this study, we design the InGaP/GaAs/Ge triple-junction solar cells by optimizing short-circuit current matching between top and middle cells using Crosslight APSYS software. The base thickness of top InGaP cell is optimized at 0.36 um and the base thickness of middle GaAs cell is optimized at 3.2 um under AM1.5G illumination. For the optimized solar cell with nanorod arrays surface texture structure, the maximum Isc is 13.512 mA/cm2, the open-circuit voltage (Voc) is 2.614 V, and the conversion efficiency (η) is 30.686 %. The enhancement of the Isc and the efficiency were 13.68 % and 12.24 %.
{"title":"Optimum design of InGaP/GaAs/Ge triple-junction solar cells with sub-wavelength surface texture structure","authors":"Pei-Hsuan Huang, Hsun-Wen Wang, M. Tsai, F. Lai, S. Kuo, H. Kuo, S. Chi","doi":"10.1109/PVSC.2011.6186360","DOIUrl":"https://doi.org/10.1109/PVSC.2011.6186360","url":null,"abstract":"In this study, we design the InGaP/GaAs/Ge triple-junction solar cells by optimizing short-circuit current matching between top and middle cells using Crosslight APSYS software. The base thickness of top InGaP cell is optimized at 0.36 um and the base thickness of middle GaAs cell is optimized at 3.2 um under AM1.5G illumination. For the optimized solar cell with nanorod arrays surface texture structure, the maximum Isc is 13.512 mA/cm2, the open-circuit voltage (Voc) is 2.614 V, and the conversion efficiency (η) is 30.686 %. The enhancement of the Isc and the efficiency were 13.68 % and 12.24 %.","PeriodicalId":373149,"journal":{"name":"2011 37th IEEE Photovoltaic Specialists Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115517831","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 : 2011-06-19DOI: 10.1109/PVSC.2011.6186034
S. Kim, H. C. Lee, W. Y. Kim, J. W. Park, J. Chung, S. Ahn, H. Lee
In this paper, a series of microcrystalline silicon (μc-Si:H) solar cells were fabricated on different back reflectors by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD). The results indicated that the performance of μc-Si:H solar cells strongly depended on their back reflector structures. First of all, the various Al:ZnO films with different optical and electrical properties were fabricated, and the effects on the performance of μc-Si:H solar cells as the back reflector materials were investigated. Unlike the previous studies for a-Si:H solar cells, all the μc-Si:H cells with various Al:ZnO back reflectors are showing similar I-V characteristics. However, it was interesting result that the back reflector with highest resistivity, fabricated by oxygen reactive sputtering, showed the best fill factor. As the next step, the n-μc-SiO layer with high resistivity was introduced as the new back reflector materials substituting for the conventional Al:ZnO. The optimal deposition condition for the n-μc-SiO layer was selected considering the low refractive index under 1.85, the reasonable electrical resistivity around 1E+3 Ω·cm and low absorption spectra near IR region. For the new back reflector structures, all the cell parameters were increased drastically at n-μc-SiO thicker than 300 nm, and a conversion efficiency of as high as 9.3 % (Voc: 0.501 V, Jsc: 27.4 mA/cm2, F.F: 0.68) was obtained. The performance gain for Voc and F.F was more obvious in the thicker back reflectors, suggesting that the high-resistivity n-μc-SiO layer could reduce the shunt current at the back contacts of μc-Si:H cells.
{"title":"Performance improvement of microcrystalline thin film silicon solar cells by back reflector with high resistivity and low absorption","authors":"S. Kim, H. C. Lee, W. Y. Kim, J. W. Park, J. Chung, S. Ahn, H. Lee","doi":"10.1109/PVSC.2011.6186034","DOIUrl":"https://doi.org/10.1109/PVSC.2011.6186034","url":null,"abstract":"In this paper, a series of microcrystalline silicon (μc-Si:H) solar cells were fabricated on different back reflectors by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD). The results indicated that the performance of μc-Si:H solar cells strongly depended on their back reflector structures. First of all, the various Al:ZnO films with different optical and electrical properties were fabricated, and the effects on the performance of μc-Si:H solar cells as the back reflector materials were investigated. Unlike the previous studies for a-Si:H solar cells, all the μc-Si:H cells with various Al:ZnO back reflectors are showing similar I-V characteristics. However, it was interesting result that the back reflector with highest resistivity, fabricated by oxygen reactive sputtering, showed the best fill factor. As the next step, the n-μc-SiO layer with high resistivity was introduced as the new back reflector materials substituting for the conventional Al:ZnO. The optimal deposition condition for the n-μc-SiO layer was selected considering the low refractive index under 1.85, the reasonable electrical resistivity around 1E+3 Ω·cm and low absorption spectra near IR region. For the new back reflector structures, all the cell parameters were increased drastically at n-μc-SiO thicker than 300 nm, and a conversion efficiency of as high as 9.3 % (Voc: 0.501 V, Jsc: 27.4 mA/cm2, F.F: 0.68) was obtained. The performance gain for Voc and F.F was more obvious in the thicker back reflectors, suggesting that the high-resistivity n-μc-SiO layer could reduce the shunt current at the back contacts of μc-Si:H cells.","PeriodicalId":373149,"journal":{"name":"2011 37th IEEE Photovoltaic Specialists Conference","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115578689","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 : 2011-06-19DOI: 10.1109/PVSC.2011.6185837
M. Contreras, L. Mansfield, B. Egaas, Jian V. Li, M. Romero, R. Noufi, Eveline Rudiger-Voigt, W. Mannstadt
This report outlines improvements to the energy conversion efficiency in wide bandgap (Eg>1.2 eV) solar cells based on CuIn1−xGaxSe2. Using (a) alkaline containing high temperature glass substrates, (b) elevated substrate temperatures 600°C-650°C and (c) high vacuum evaporation from elemental sources following NREL's three-stage process, we have been able to improve the performance of wider bandgap solar cells with 1.218% for absorber bandgaps ∼1.30 eV and efficiencies ∼16% for bandgaps up to ∼1.45 eV. In comparing J-V parameters in similar materials, we establish gains in the open-circuit voltage and, to a lesser degree, the fill factor value, as the reason for the improved performance. The higher voltages seen in these wide gap materials grown at high substrate temperatures may be due to reduced recombination at the grain boundary of such absorber films. Solar cell results, absorber materials characterization, and experimental details are reported.
{"title":"Improved energy conversion efficiency in wide bandgap Cu(In, Ga)Se2 solar cells","authors":"M. Contreras, L. Mansfield, B. Egaas, Jian V. Li, M. Romero, R. Noufi, Eveline Rudiger-Voigt, W. Mannstadt","doi":"10.1109/PVSC.2011.6185837","DOIUrl":"https://doi.org/10.1109/PVSC.2011.6185837","url":null,"abstract":"This report outlines improvements to the energy conversion efficiency in wide bandgap (Eg>1.2 eV) solar cells based on CuIn1−xGaxSe2. Using (a) alkaline containing high temperature glass substrates, (b) elevated substrate temperatures 600°C-650°C and (c) high vacuum evaporation from elemental sources following NREL's three-stage process, we have been able to improve the performance of wider bandgap solar cells with 1.2<Eg<1.45 eV. Initial results of this work have led to efficiencies >18% for absorber bandgaps ∼1.30 eV and efficiencies ∼16% for bandgaps up to ∼1.45 eV. In comparing J-V parameters in similar materials, we establish gains in the open-circuit voltage and, to a lesser degree, the fill factor value, as the reason for the improved performance. The higher voltages seen in these wide gap materials grown at high substrate temperatures may be due to reduced recombination at the grain boundary of such absorber films. Solar cell results, absorber materials characterization, and experimental details are reported.","PeriodicalId":373149,"journal":{"name":"2011 37th IEEE Photovoltaic Specialists Conference","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115862206","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 : 2011-06-19DOI: 10.1109/PVSC.2011.6186393
P. J. Richter, F. Bottari, D. C. Wong
Co-firing of crystalline silicon solar cell metal contacts in infrared conveyor furnaces is the standard of the industry today. Typical ramp rates of 60–80°C./s. and total firing times of approximately 16 to 20 seconds are used due to limitations inherent in currently available production equipment. We report on a novel industrial-scale process utilizing ramp rates as high as 400°C./s. and high cooling rates which result in total firing times of 1.09 to 1.72 seconds. Cells have been produced with this process with measured fill factors in excess of 80% and high shunt resistance. At the lower firing times in this experimental series, high fill factors were maintained but open circuit voltage (Voc) reduced indicating non-optimal back surface field (BSF) formation. This study addresses the requirements for aluminum BSF formation in very rapid co-firing.
{"title":"Rapid metallization paste firing of crystalline silicon solar cells","authors":"P. J. Richter, F. Bottari, D. C. Wong","doi":"10.1109/PVSC.2011.6186393","DOIUrl":"https://doi.org/10.1109/PVSC.2011.6186393","url":null,"abstract":"Co-firing of crystalline silicon solar cell metal contacts in infrared conveyor furnaces is the standard of the industry today. Typical ramp rates of 60–80°C./s. and total firing times of approximately 16 to 20 seconds are used due to limitations inherent in currently available production equipment. We report on a novel industrial-scale process utilizing ramp rates as high as 400°C./s. and high cooling rates which result in total firing times of 1.09 to 1.72 seconds. Cells have been produced with this process with measured fill factors in excess of 80% and high shunt resistance. At the lower firing times in this experimental series, high fill factors were maintained but open circuit voltage (Voc) reduced indicating non-optimal back surface field (BSF) formation. This study addresses the requirements for aluminum BSF formation in very rapid co-firing.","PeriodicalId":373149,"journal":{"name":"2011 37th IEEE Photovoltaic Specialists Conference","volume":"358 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115866694","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 : 2011-06-19DOI: 10.1109/PVSC.2011.6185919
Y. Aya, H. Katayama, M. Matsumoto, M. Hishida, W. Shinohara, I. Yoshida, A. Kitahara, H. Yoneda, A. Terakawa, M. Iseki
The technology to make high-quality, high-reliability solar modules with a high deposition rate for μc-Si thin-film is a problem for the industrialization of low-cost, high-conversion-efficiency a-Si/μc-Si tandem structure solar modules. Sanyo has solved this problem by developing an original CVD technique called Localized Plasma Confinement CVD and a new evaluation method for μc-Si thin film. A stabilized conversion efficiency of 10.0% was achieved for an a-Si/μc-Si tandem structure solar module, and a deposition rate of 2.4 nm/s for μc-Si thin-film was attained on a Gen. 5.5 full-size glass substrate. To obtain a higher conversion-efficiency a-Si/μc-Si tandem structure solar module, fundamental studies of μc-Si thin-film have been performed, and a stabilized conversion efficiency of 10.5% (Initial solar module conversion efficiency: 12.0%) has been achieved on a large-area glass substrate. Furthermore, in the study of this development, the highest stabilized conversion efficiency of 12.0% (Initial conversion-efficiency: 13.5%) was attained. Module reliability tests confirmed by IEC 61646 Ed. 2 revealed that the performance of the module is adapted. These high-performance a-Si/μc-Si tandem structure solar modules were prepared by using the knowledge of our thin-film and module technologies.
制备高质量、高可靠性、高沉积速率的μc-Si薄膜太阳能组件是实现低成本、高转换效率a- si /μc-Si串联结构太阳能组件产业化的关键技术。三洋解决了这一问题，开发了一种新颖的CVD技术，称为局部等离子体约束CVD和一种新的μc-Si薄膜评价方法。A -si /μc-Si串联结构太阳能组件的转换效率稳定在10.0%，μc-Si薄膜在Gen. 5.5全尺寸玻璃衬底上的沉积速率为2.4 nm/s。为了获得更高转换效率的a- si /μc-Si串联结构太阳能组件，对μc-Si薄膜进行了基础研究，在大面积玻璃衬底上实现了10.5%的稳定转换效率(初始太阳能组件转换效率为12.0%)。此外，在这一发展的研究中，最高稳定转换效率为12.0%(初始转换效率为13.5%)。通过IEC 61646 Ed. 2验证的模块可靠性测试表明，该模块的性能是适应的。这些高性能的a-Si/μc-Si串联结构太阳能组件是利用我们的薄膜和组件技术知识制备的。
{"title":"Progress in the development of high-conversion-efficiency a-Si/μc-Si tandem solar module using μc-Si thin film with high deposition rate on Gen. 5.5 large-area glass substrate","authors":"Y. Aya, H. Katayama, M. Matsumoto, M. Hishida, W. Shinohara, I. Yoshida, A. Kitahara, H. Yoneda, A. Terakawa, M. Iseki","doi":"10.1109/PVSC.2011.6185919","DOIUrl":"https://doi.org/10.1109/PVSC.2011.6185919","url":null,"abstract":"The technology to make high-quality, high-reliability solar modules with a high deposition rate for μc-Si thin-film is a problem for the industrialization of low-cost, high-conversion-efficiency a-Si/μc-Si tandem structure solar modules. Sanyo has solved this problem by developing an original CVD technique called Localized Plasma Confinement CVD and a new evaluation method for μc-Si thin film. A stabilized conversion efficiency of 10.0% was achieved for an a-Si/μc-Si tandem structure solar module, and a deposition rate of 2.4 nm/s for μc-Si thin-film was attained on a Gen. 5.5 full-size glass substrate. To obtain a higher conversion-efficiency a-Si/μc-Si tandem structure solar module, fundamental studies of μc-Si thin-film have been performed, and a stabilized conversion efficiency of 10.5% (Initial solar module conversion efficiency: 12.0%) has been achieved on a large-area glass substrate. Furthermore, in the study of this development, the highest stabilized conversion efficiency of 12.0% (Initial conversion-efficiency: 13.5%) was attained. Module reliability tests confirmed by IEC 61646 Ed. 2 revealed that the performance of the module is adapted. These high-performance a-Si/μc-Si tandem structure solar modules were prepared by using the knowledge of our thin-film and module technologies.","PeriodicalId":373149,"journal":{"name":"2011 37th IEEE Photovoltaic Specialists Conference","volume":"209 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115926378","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 : 2011-06-19DOI: 10.1109/PVSC.2011.6186634
P. Mints
The grid connected application, at >95% of demand, consumes gigawatts of photovoltaic product annually, and yet, remains volatile and risky in terms of its primary driver: incentives. As incentive structures change, becoming less profitable for investors and consumers, other methods of driving the market will need to be developed. Yet, observing PV industry history, the feed in tariff (FiT), the most successful market stimulation tool for PV, has a relatively short history. This paper will explore the role of incentives in the PV industry from the 1970s to present, including degressions in incentive rates over time, observe current trends towards tender processes to set rates, caps, REC trading schemes (essentially commodity trading) and cessation of incentives altogether while exploring business models that will continue to drive growth with or without incentive structures. This paper will also explore the beginnings and market dominance of multi-megawatt ground mount installations, a phenomenon that came about specifically because of the FiT incentive.
{"title":"Changing incentive structures and photovoltaic demand","authors":"P. Mints","doi":"10.1109/PVSC.2011.6186634","DOIUrl":"https://doi.org/10.1109/PVSC.2011.6186634","url":null,"abstract":"The grid connected application, at >95% of demand, consumes gigawatts of photovoltaic product annually, and yet, remains volatile and risky in terms of its primary driver: incentives. As incentive structures change, becoming less profitable for investors and consumers, other methods of driving the market will need to be developed. Yet, observing PV industry history, the feed in tariff (FiT), the most successful market stimulation tool for PV, has a relatively short history. This paper will explore the role of incentives in the PV industry from the 1970s to present, including degressions in incentive rates over time, observe current trends towards tender processes to set rates, caps, REC trading schemes (essentially commodity trading) and cessation of incentives altogether while exploring business models that will continue to drive growth with or without incentive structures. This paper will also explore the beginnings and market dominance of multi-megawatt ground mount installations, a phenomenon that came about specifically because of the FiT incentive.","PeriodicalId":373149,"journal":{"name":"2011 37th IEEE Photovoltaic Specialists Conference","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124102793","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}
The innovative passivation treatment has been developed for increasing the stabilized power of standard a-Si/μc-Si tandem module and building-integrated photovoltaic (BIPV) via well passivation of μc-Si material. By adopting external passivation technique, the open-circuit voltage (Voc) almost keeps in constant, furthermore, a significant improvement of Voc (∼3%) and fill factor (∼5%) could be obtained as comparing to reference ones. In the present work, a well passivation treatment for microcrystalline Si to prevent the post-oxidation of the cracks has been reported. About 9 % of improvement of degradation behavior and an outstanding performance of BIPV (93%) could be observed by this unique technique.
{"title":"Innovative passivation for reducing degradation of a-Si/uc-Si tandem photovaltaic module","authors":"Chih-Wei Chang, Ching-In Wu, Kai-Hsiang Chuang, Chih-Hsiung Chang, K. Lin, Chin-Yao Tsai","doi":"10.1109/PVSC.2011.6186573","DOIUrl":"https://doi.org/10.1109/PVSC.2011.6186573","url":null,"abstract":"The innovative passivation treatment has been developed for increasing the stabilized power of standard a-Si/μc-Si tandem module and building-integrated photovoltaic (BIPV) via well passivation of μc-Si material. By adopting external passivation technique, the open-circuit voltage (Voc) almost keeps in constant, furthermore, a significant improvement of Voc (∼3%) and fill factor (∼5%) could be obtained as comparing to reference ones. In the present work, a well passivation treatment for microcrystalline Si to prevent the post-oxidation of the cracks has been reported. About 9 % of improvement of degradation behavior and an outstanding performance of BIPV (93%) could be observed by this unique technique.","PeriodicalId":373149,"journal":{"name":"2011 37th IEEE Photovoltaic Specialists Conference","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114365970","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 : 2011-06-19DOI: 10.1109/PVSC.2011.6185892
Y. Lee, M. Winkler, S. Siah, R. Brandt, T. Buonassisi
Copper (I) oxide (Cu2O) is considered a promising material for low-cost photovoltaic applications. In this contribution, high-quality Cu2O films are prepared by reactive dc magnetron sputtering. We optimize deposition parameters to achieve pure Cu2O-phase thin films. We report the control of electrical, optical, and structural properties of the resulting films by varying the substrate temperature during film growth, and carefully controlling other growth parameters. We achieve a columnar grain structure with the large average grain size (884±373 nm) and high-mobility (62 cm2/V·s) at room temperature. All films exhibit an optical bandgap between 1.9 and 2.0 eV, and the samples grown at high temperature show enhanced optical transmission at wavelengths greater than 600 nm.
{"title":"High-mobility copper (I) oxide thin films prepared by reactive dc magnetron sputtering for photovoltaic applications","authors":"Y. Lee, M. Winkler, S. Siah, R. Brandt, T. Buonassisi","doi":"10.1109/PVSC.2011.6185892","DOIUrl":"https://doi.org/10.1109/PVSC.2011.6185892","url":null,"abstract":"Copper (I) oxide (Cu2O) is considered a promising material for low-cost photovoltaic applications. In this contribution, high-quality Cu2O films are prepared by reactive dc magnetron sputtering. We optimize deposition parameters to achieve pure Cu2O-phase thin films. We report the control of electrical, optical, and structural properties of the resulting films by varying the substrate temperature during film growth, and carefully controlling other growth parameters. We achieve a columnar grain structure with the large average grain size (884±373 nm) and high-mobility (62 cm2/V·s) at room temperature. All films exhibit an optical bandgap between 1.9 and 2.0 eV, and the samples grown at high temperature show enhanced optical transmission at wavelengths greater than 600 nm.","PeriodicalId":373149,"journal":{"name":"2011 37th IEEE Photovoltaic Specialists Conference","volume":"256 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114401690","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 : 2011-06-19DOI: 10.1109/PVSC.2011.6186499
M. F. Budiman, Xuan-Yu Wang, Chi-Hsien Huang, R. Tsukamoto, T. Kaizu, M. Igarashi, P. Mortemousque, Y. Okada, A. Murayama, K. Itoh, Y. Ohno, S. Samukawa
A series of damage-free fabrication processes for a two-dimensional array of sub-10-nm GaAs nanodiscs was developed by using bio-templates and neutral beam etching. The photoluminescence of GaAs etched with a neutral beam clearly revealed that the processes could accomplish defect-free etching for GaAs. In the bio-template process, a hydrogen-radical treatment was used to remove the native oxide on the GaAs surface, and then neutral beam oxidation (NBO) was used to form a hydrophilic 1-nm-thick GaAs oxide (GaAs-NBO) film. The two-dimensional array of ferritins (protein including a 7-nm-diameter iron core) can be arranged well on hydrophilic GaAs-NBO film. The ferritin protein shell was removed using an oxygen-radical treatment at a low temperature of 280°C without thermal damage to the GaAs. Then, the neutral beam etched the the GaAs to form defect-free nanodisc structure of using the iron core as an etching mask. Finally, the iron oxide core was removed by wet etching with diluted hydrogen chloride and the fabrication process was completed without inflicting any damage to the GaAs. As a result, a two-dimensional array of GaAs quantum dots with a diameter of ∼7 nm, a height of ∼10 nm, a high taper angle of 88°, and a quantum dot density of more than 7×1011 cm−2 was successfully fabricated without causing any damage to the GaAs.
{"title":"Damage-free top-down processes for fabricating two-dimensional array of sub-10-nanometer GaAs nanodiscs using bio-template and neutral beam etching for intermediate band solar cell applications","authors":"M. F. Budiman, Xuan-Yu Wang, Chi-Hsien Huang, R. Tsukamoto, T. Kaizu, M. Igarashi, P. Mortemousque, Y. Okada, A. Murayama, K. Itoh, Y. Ohno, S. Samukawa","doi":"10.1109/PVSC.2011.6186499","DOIUrl":"https://doi.org/10.1109/PVSC.2011.6186499","url":null,"abstract":"A series of damage-free fabrication processes for a two-dimensional array of sub-10-nm GaAs nanodiscs was developed by using bio-templates and neutral beam etching. The photoluminescence of GaAs etched with a neutral beam clearly revealed that the processes could accomplish defect-free etching for GaAs. In the bio-template process, a hydrogen-radical treatment was used to remove the native oxide on the GaAs surface, and then neutral beam oxidation (NBO) was used to form a hydrophilic 1-nm-thick GaAs oxide (GaAs-NBO) film. The two-dimensional array of ferritins (protein including a 7-nm-diameter iron core) can be arranged well on hydrophilic GaAs-NBO film. The ferritin protein shell was removed using an oxygen-radical treatment at a low temperature of 280°C without thermal damage to the GaAs. Then, the neutral beam etched the the GaAs to form defect-free nanodisc structure of using the iron core as an etching mask. Finally, the iron oxide core was removed by wet etching with diluted hydrogen chloride and the fabrication process was completed without inflicting any damage to the GaAs. As a result, a two-dimensional array of GaAs quantum dots with a diameter of ∼7 nm, a height of ∼10 nm, a high taper angle of 88°, and a quantum dot density of more than 7×1011 cm−2 was successfully fabricated without causing any damage to the GaAs.","PeriodicalId":373149,"journal":{"name":"2011 37th IEEE Photovoltaic Specialists Conference","volume":"389 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114504720","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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