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Chemical stoichiometry along with depth profiling and metallic contamination is of considerable interest for photovoltaic thin films. Conversion efficiency can be affected for example if primary components, e.g. Cd and Te, are not present at proper ratios. Moreover, amorphous silicon can vary substantially between sources and deposition technique, and qualitative comparison of trace metallic contaminants may not be sufficient to ensure final thin-film quality. This discussion presents data from atomic emission and mass spectrometry techniques that quantitatively and accurately describe both bulk and trace elemental compositions in photovoltaic materials, various thin-film matrices, and the final thin-film cell and module.

The recent photovoltaic industry shakeout which started around Q3 2008 has faced the overcapacity, credit crunch, and economic crisis that significantly declined the average selling price by 50-65%, including the price of thin-film photovoltaic modules. The changing business environment has put significant pressure on all PV manufacturing technologies but more candidly on amorphous silicon thin-film single-junction module manufacturers to advance and scale up the device efficiency and aggressively drive cost reduction. This paper outlines the technical approach taken at Moser Baer Photovoltaic Technologies India Limited (PVTIL), including process optimization and device
management strategies, to enhance the efficiency (total area) of the thin-film single-junction amorphous silicon module as manufactured using Applied Materials' SunFab line.

It is widely acknowledged that, without government subsidies, solar power still cannot compete effectively with conventional sources of electrical energy. As the industry strives to make solar electricity affordable and as a viable alternative to fossil fuels, solar power technology companies are diligently moving towards reducing the manufacturing cost for solar modules. In the case of thin-film solar cells in particular, as a benchmark, the cost of for solar power must be reduced for it to be competitive or to attain grid parity. This paper presents a number of opinions from industry leaders on how best to decrease this vital cost.

Highly conductive transparent films are of significant interest in the field of thin-film photovoltaics. ZnO-based films in particular have attracted much interest due to the low cost of materials with good film properties for CIGS and a-Si/µc-Si solar modules. Investigations have been ongoing at Fraunhofer IST into ceramic ZnO:Al₂O₃ targets from different manufacturers. This paper presents a comparison of target material, sputter characteristics and film properties of ZnO:Al. Sputter characteristics are in this case determined by voltage and current data showing arcing rates at different power loads and process pressures. ZnO:Al films are deposited by DC magnetron sputtering with various deposition parameters (e.g oxygen flow, total pressure, sputtering power and substrate temperature) and investigated with respect to optical and electrical properties.

During the past few years, electroluminescence imaging has become a standard characterization technique for failure analysis and qualification of silicon wafer-based solar cells and modules. In contrast, the same analysis is not yet widely used for thin-film modules. This article demonstrates that electroluminescence analysis is a highly suitable tool for the in-depth investigation of Cu(In,Ga)Se₂ thin-film solar modules as well as for standard quality control. The reciprocity between the photovoltaic action and the electroluminescence emission of solar cell devices is used to derive quantitative relations that describe the voltage distribution within a solar module. Individual shunt spots in a module are not only visualized but their influence on the current voltage curves of the individual cells is quantitatively analyzed. Furthermore, device parameters like the sheet resistances of the window layer and the back contact are derived from the electroluminescence images

Outside of the challenges of fabricating state-of-the-art photovoltaic devices, further care must be taken to package them such that they can withstand environmental conditions for an accepted lifetime of 20-plus years. Moisture ingress is a big adversary to hermetic packaging. The diffusion of water through barriers and edge seals can be minimized by careful choice of materials and package/barrier architecture. However, at present, there exist no solutions for extremely water-sensitive materials for flexible applications. Presented in the following is a review of the physics of permeation, the means of measuring permeation, current architectural strategies for semi-hermetic packages, and a brief evaluation of some common encapsulant materials.

Among the various thin-film solar module options available, CIGS is especially interesting as it exhibits the highest efficiency potential. These chalcopyrite-based solar cells are manufactured on glass or flexible substrates using various thin-film coating methods for each layer. The central CIGS absorber layer is deposited by co-evaporation, selenization of elemental layers, and other methods. In order to achieve highest quality and reproducibility, the absorber properties must be properly monitored and characterized. In this contribution we shed some light on the most important analysis methods used for CIGS solar cell research, development, and production such as x-ray fluorescence, surface analysis, and Raman spectroscopy.

Until the year 2002, wafer-based crystalline silicon solar cells were almost exclusively the solar cell technology used for large-scale power plants. Since then, steady growth in the market share for thin-film technologies has been observed, although crystalline silicon technology still remains the most important solar cell technology used in large-scale PV power plants. The market share of thin-film modules, especially CdTe modules, has been continuously increasing in recent years, most notably in the German market. However, other countries like Spain, the USA, Italy and France have seen some large-scale CdTe-based modules being installed in power plants recently.

At First Solar’s corporate headquarters in Tempe, Arizona, a morale-boosting slogan adorns posters stuck to the outside of cubicle partitions: “MILESTONE MADE! TEN ONE ONE.” That’s “Ten,” for 10 years in business – at least in the company’s First Solar incarnation. The original firm Glasstech Solar, led by visionary Harold McMaster, actually set up shop in 1984, then became Solar Cells, Inc. in 1992, which begat the present entity in 1999. The middle “One” stands for the gigawatt’s worth of panels produced in the solar module factories in Ohio, Germany, and Malaysia – as well as the annual production capacity that will be ramped by the end of 2009. The final “One” stands for perhaps the biggest accomplishment of all – the dollar-per-manufactured-watt standard beaten by two cents by First Solar in the final quarter of 2008, a cost that has since shrunk to 93 cents per watt in the first quarter of 2009. But then, “Ten/One/0.93” doesn’t quite have the same ring.

A variety of thin-film technologies are now entering a volume manufacturing phase. The benchmark has already been set by First Solar, Inc. in its conversion efficiencies, volume ramp and lowest cost-per-watt in the PV industry. Large-area thin-film deposition is a critical process step, dictating cell performance, reliability and manufacturing throughput. However, adoption of thin-film solar cells has been limited in the past by relatively complex and costly manufacturing processes. The advent of rotating cylindrical magnetrons for sputtering is demonstrating the potential to significantly reduce thin-film manufacturing costs. In this paper we discuss the basics of the technology and the developments taking place with some of the leading suppliers of sputtering target technology for the PV industry.