Author: Francis Yee-Tat KaiPublisher:
ISBN:
Category :
Languages : en
Pages : 422
Book Description
Grain Boundary Effects and Passivation Studies in Polycrystalline Mis Solar Cells
Author: Francis Yee-Tat KaiThe Influence of Grain Boundaries on Solar Cell Performance
Author: Joseph B. MilsteinPublisher:
ISBN:
Category : Grain boundaries
Languages : en
Pages : 6
Book Description
Grain boundary studies related to polycrystalline silicon solar cells are reviewed. Included in this paper are discussions of grain boundary effects, models and passivation methods. Major problem areas that need further studies are discussed.
Spatially-Resolved Studies of Grain-Boundary Effects in Polycrystalline Solar Cells Using Micro-Photoluminescence and Near-Field Microscopy
Author: S. SmithPublisher:
ISBN:
Category :
Languages : en
Pages : 5
Book Description
Photoluminescence and photocurrent spectroscopies combined with diffraction-limited and sub- diffraction-limited spatial resolution are achieved via micro-photoluminescence (m-PL) and near-field microscopy (NSOM). These methods are used to examine the photo-response of individual grain boundaries in thin-film, polycrystalline solar cells at room and cryogenic temperatures. A systematic m-PL study of the effect of CdCl2-treatment on recombination in CdTe/CdS solar cell structures of varying thickness directly reveals the grain-boundary and surface passivation action of this important post-growth processing step. We achieve 50nm (l/10) spatial resolution in near-field Optical Beam Induced Current imaging (n-OBIC) of polycrystalline silicon solar cells using NSOM, at varying stages of silicon nitride grain-boundary passivation, and measure lateral variations in photo-response of CdTe/CdS solar cells with subwavelength spatial resolution.
Solar Energy Update
Author: Fundamental Studies of Grain Boundary Passivation in Polycrystalline Silicon with Application to Improved Photovoltaic Devices. A Final Research Report Covering Work Completed from February-December 1979
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Several aspects of the electrical properties of silicon grain boundaries have been studied. The temperature dependence of the zero-bias conductance and capacitance of single boundaries has been measured and shown to be in good agreement with a simple double depletion layer/thermal emission (DDL/TE) model developed to predict the transport properties of such structures. In addition, it has been shown that deconvolution of the I-V properties of some boundaries via a deconvolution scheme suggested by Pike and Seager yields effective one-electron densities of trapping states which are in good agreement with estimates obtained by low temperature electron emission measurements. Experiments have also been performed which indicate that diffusion of atomic hydrogen into silicon grain boundaries greatly reduces this density of trapping states. In properly prepared, large grained polycrystalline samples all measurable traces of grain boundary potential barriers can be removed to substantial penetration depths after several hours exposure to a hydrogen plasma at elevated temperatures. Initial experiments on prototype polysilicon solar cells have shown that this passivation process can improve AM1 efficiencies. In order to more fully understand and develop this process for improving practical multigrained cells, several device research efforts with other DOE/SERI funded contractors have been initiated.
Grain-boundary Physics in Polycrystalline Photovoltaic Materials
Author: Publisher:
ISBN:
Category : Photovoltaic cells
Languages : en
Pages : 4
Book Description
We use the combination of high-resolution electron microscopy and density-functional theory to study the atomic structure and electronic effects of grain boundaries in polycrystalline photovoltaic materials such as Si, CdTe, CuInSe2, and CuGaSe2. We find that grain boundaries containing dislocation cores create deep levels in Si, CdTe, and CuGaSe2. Surprisingly, however, they do not create deep levels in CuInSe2. We further find that the presence of Ga in grain boundaries in CuInSe2 generates deep levels. These results may explain the fact that Si and CdTe solar cells usually require special passivation, whereas CuInSe2 solar cells do not. The passivation of grain boundaries in Si and CdTe is also studied. We find that grain boundaries in CdTe can be passivated very well by Cl, Br, and I.
Scientific and Technical Aerospace Reports
Author: Focus on Polycrystalline Thin Film Cells
Author: Energy Research Abstracts
Author: Fundamental Studies of Grain Boundary Passivation in Polycrystalline Silicon with Application to Improved Photovoltaic Devices. A Research Report Covering Work Completed from February 1981 to January 1982
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Grain boundary barrier heights and other properties were measured on a variety of Wacker poly-Si to test the contention of Redfield that as received samples had no potential barriers and that temperature anneals activate the impurities in the boundaries. Our results show that these generalizations are not true and that a variety of barrier behaviors are found. Several of our new analytical techniques for studying grain boundaries and their passivation have been upgraded, including a new cell for Fourier Transform Infrared (FTIR) studies, electrochemical techniques, and a laser scanning apparatus for imaging grain boundaries. Grain boundaries in a variety of samples have been successfully passivated by the use of both the Kaufman ion source and a dc discharge apparatus. 20% improvements in cell efficiencies have been observed in large grained poly-Si cells, and the time of treatment has been drastically reduced.