In situ analysis of elemental depth distributions in thin films by combined evaluation of synchrotron x ray fluorescence and diffraction

Abstract In this work we present a method for in situ analysis of elemental depth distributions in thin films by a combined evaluation of synchrotron x ray fluorescence XRF and energy dispersive x ray diffraction EDXRD signals. We recorded diffraction and fluorescence signals simultaneously during reactive annealing of thin films. By means of the observed diffraction signals the time evolution of phases in the thin films during the annealing processes can be determined. We utilized this phase information to parameterize depth distributions of the elements in the films. The time dependent fluorescence signals were then taken to determine the parameters representing the parameterized depth distributions. For this latter step, we numerically calculated fluorescence intensities for a given set of depth distributions. These calculations handle polychromatic excitation and arbitrary functions of depth distributions and take into account primary and secondary fluorescence. The influence of lateral non uniformity of the films as well as accuracy limits of the method are investigated. We apply the introduced method to analyze the evolution of elemental depths distributions and to quantify kinetic parameters during a synthesis process of CuInS2 thin films by reactive annealing of Cu In precursors in sulfur atmospher

Strengthening Resilience by thinking of Knowledge as a nutrient connecting the local person to global thinking: The case of Social Technology/Tecnologia Social

In this chapter, we describe the Knowledge as a Nutrient framework that emerged from these conversations. We describe how it relates to the Tecnologia Social policy approach to sustainability, developed in Brazil (Dagnino et al. 2004, Fundação Banco do Brasil 2009, Costa 2013), which is not well known in the anglophone world. Tecnologia Social was both inspired by and rooted in Paulo Freire’s pedagogical thinking (2000, Klix 2014).   We show how this framework has the potential to increase community resilience and adaptive capacity, not only for communities that face and must adapt to climate change but for all communities in the throes of complex social, ecological, economic and political transitions.This research was supported by the International Development Research Centre, grant number IDRC GRANT NO. 106002-00

Progress in the development of CuInS2 based mini modules

A sequential process is used to synthesise CuInS2 absorber layers for photovoltaic application. In this process CuIn precursor layers sputtered on molybdenum coated float glass are converted to CuInS2 via sulphurisation in an elemental sulphur vapour ambient. A re evaluation of process parameters has been performed including fine tuning of numerous minor aspects. Using optimised process conditions has lead to improved device performance, especially a narrowed distribution at higher module efficiencies is achieved. At the same time the process yield is improved resulting in fewer devices with poor electrical qualit

How will disenfranchised Peoples adapt to Climate Change? Strengthening the Ecojustice Movement

The Fourth assessment of the Intergovernmental Panel on Climate Change (IPCC) acknowledged That millions of people are currently, and will increasingly be, affected by the impacts of climate change, in the form of floods, droughts and other extreme events, as well as related threats to food security. In response to these global environmental changes, the international community, including civil society, is acting on the need for immediate adaptation measures and is developing strategies for future adaptation. However, the impacts of climate change are unevenly distributed, with many of the poorest, most vulnerable peoples experiencing the immediate effects of climate change, in the here and now. As the IPCC noted, developing countries are disproportionately affected by climate change and often, the least able to adapt due to lack of infrastructure and resources

Stability of plasmonic metal nanoparticles integrated in the back contact of ultra-thin Cu(In,Ga)S2 solar cells

Ultra-thin solar cells on transparent back contacts constitute the basis for highly efficient tandem solar devices which can surpass the single cell efficiency limit. The material reduction related to ultra-thin high efficiency devices additionally lowers the price. Despite the fact that they are ultra- thin the absorbers still have to remain optically thick and therefore require adequate light management. A promising approach for enhanced absorption is plasmonic scattering from metal nanoparticles. In this paper we discuss the experimental incorporation of Ag nanoparticles in ultra-thin wide-gap chalcopyrite solar cells on transparent back contacts. A 6.9% efficient 500 nm Cu(In,Ga)S2 solar cell on In2O3:Mo (at this point without nanoparticles) is the starting point. For the predicted optimum design of including particles at the rear side the stability of the nanostructures integrated in the back contact is investigated in detail. As a first step towards proof-of-concept, absorption enhancement from the nanoparticles included in the complete solar cell is experimentally shown in optical properties

Raman and photoreflectance study of Cu In,Ga S2 films and solar cells

The structural and optical properties of CuIn1 xGaxS2 CIGS , CdS CuIn1 xGaxS2, and ZnO CdS CuIn1 xGaxS2 polycrystalline films, with applications in photovoltaics, were studied by Raman and Photoreflectance PR spectroscopy for two different compositions, [Ga] [In] [Ga] 0.04 and 0.12, of the CuIn1 xGaxS2 absorber. The energy band gap of the absorber film was determined by fitting the PR spectra with a third derivative functional form. Moreover, the thickness of the film was calculated from the interference fringes observed in the PR spectra below band gap energy. Raman scattering was excited by the 514.5nm line of Ar laser and the 647.1nm line of Kr laser. The Raman spectra of the absorber films consist of phononmodes assigned to CuInS2, CuGaS2 and CuS. The results of the present study are discussed together with the results of SEM and XRD studies of the films and the results of electrical measurements performed on solar cells based on the CIGS absorber

Zn(O, S) layers for chalcoyprite solar cells sputtered from a single target

A simplified Cu(In, Ga)(S, Se)2/Zn(O, S)/ZnO:Al stack for chalcopyrite thin- film solar cells is proposed. In this stack the Zn(O, S) layer combines the roles of the traditional CdS buffer and undoped ZnO layers. It will be shown that Zn(O, S) films can be sputtered in argon atmosphere from a single mixed target without substrate heating. The photovoltaic performance of the simplified stack matches that of the conventional approach. Replacing the ZnO target with a ZnO/ZnS target may therefore be sufficient to omit the CdS buffer layer and avoid the associated complexity, safety and recycling issues, and to lower production cost

Nimbus 7 solar backscatter ultraviolet (SBUV) ozone products user's guide

Three ozone tape products from the Solar Backscatter Ultraviolet (SBUV) experiment aboard Nimbus 7 were archived at the National Space Science Data Center. The experiment measures the fraction of incoming radiation backscattered by the Earth's atmosphere at 12 wavelengths. In-flight measurements were used to monitor changes in the instrument sensitivity. Total column ozone is derived by comparing the measurements with calculations of what would be measured for different total ozone amounts. The altitude distribution is retrieved using an optimum statistical technique for the inversion. The estimated initial error in the absolute scale for total ozone is 2 percent, with a 3 percent drift over 8 years. The profile error depends on latitude and height, smallest at 3 to 10 mbar; the drift increases with increasing altitude. Three tape products are described. The High Density SBUV (HDSBUV) tape contains the final derived products - the total ozone and the vertical ozone profile - as well as much detailed diagnostic information generated during the retrieval process. The Compressed Ozone (CPOZ) tape contains only that subset of HDSBUV information, including total ozone and ozone profiles, considered most useful for scientific studies. The Zonal Means Tape (ZMT) contains daily, weekly, monthly and quarterly averages of the derived quantities over 10 deg latitude zones