Coated window glass is an integral component of year-round energy-saving strategies in modern office buildings and residences. Solar control glass ensures that heat radiation from the sun does not warm up rooms in the summer, thereby reducing energy consumed by air-conditioning systems. Conversely, a targeted coating on the interior side of the glass (low emissivity glass) enables the surface to reflect heat back into the room during winter, substantially reducing heat loss through the windowpanes. Coatings containing silver, in particular, work well to reduce heat loss and energy costs in modern buildings.
In-house lab system optimizes sputtering targets for coating glass surfaces
Materials from sputtering targets are deposited directly onto glass sheets with the help of sputtering technology. During the sputtering process, a negative electrical charge is applied to the target. Combined with the inert gas argon, this generates a high-energy discharge of gas - also called plasma - in a vacuum chamber, from which argon ions are fired at the target. The positively charged gas ions knock individual atoms off the surface of the target, which then condense on the base material as an extremely thin coating.
When it comes to development, optimization, and functional testing, researchers at Heraeus have an important in-house system to help them. The Thin Film Materials Division's research and development department conducts rapid testing on newly developed planar and tube-shaped sputtering targets with a sputtering system in its lab. "This drastically decreases development time and enables a completely new type of collaboration with our customers. The sputtering system is a key instrument in our development and optimization work," emphasizes Martin Schlott, Head of Development for the Thin Film Materials Division at Heraeus. The requirements for sputtering targets are extremely stringent. They must be of the utmost purity (99.95 to 99.999 percent), have a high density, high chemical homogeneity, a fine, homogenous microstructure, and be completely free of even the smallest flaws and pores.
Sputtering targets coat solar cells in photovoltaics
Sputtering targets from Heraeus are also used in manufacturing solar cells, particularly in thin-film photovoltaics. Layers that minimize reflection are applied during the coating process, for example. This minimizes losses arising from the unwanted reflection of solar radiation on the solar module and boosts cell efficiency. Even the absorber layer - the core element of photovoltaic cells - is sometimes produced using a sputtering process. The latest targets developed by Heraeus are also used in this application. The performance of solar cells depends on quality of this sputtered layer and especially on the coating material. (Sputtering targets at Heraeus: www.heraeus-targets.com )
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