Writer – Shannon Combs
While silicon is actually the market standard semiconductor in most electronic devices, including the photovoltaic cells that solar panels employ to convert sunlight into electricity, it is not really the most cost-efficient component available. For instance, the semiconductor gallium arsenide and similar ingredient semiconductors give nearly double the performance as silicon in solar units, but they are rarely employed in utility-scale applications mainly because of their high construction value.
U. of I. professors J. Rogers and X. Li researched lower-cost methods to produce thin films of gallium arsenide that also granted versatility in the sorts of devices they might be included into.
If you could decrease significantly the price of gallium arsenide and some other compound semiconductors, then you might increase their variety of applications.
Generally, gallium arsenide is placed in a individual thin layer on a little wafer. Either the preferred device is created right on the wafer, or the semiconductor-coated wafer is cut up into chips of the preferred size. The Illinois team considered to put in numerous levels of the material on a individual wafer, creating a layered, “pancake” stack of gallium arsenide thin films.
If you grow 10 layers in a single growth, you only have to load the wafer one time. If you do this in ten growths, loading and unloading with temperature ramp-up and ramp-down get a lot of time. If you take into account exactly what is needed for each growth – the equipment, the procedure, the period, the workers – the overhead saving this technique gives is a important price decrease.
Following the scientists separately peel off the layers and transport them. To achieve this, the stacks alternate layers of aluminum arsenide with the gallium arsenide. Bathing the stacks in a formula of acid and an oxidizing agent dissolves the layers of aluminum arsenide, freeing the single small sheets of gallium arsenide. A soft stamp-like system picks up the layers, just one at a time from the top down, for exchange to another substrate – glass, plastic-type or silicon, based on the application. Then the wafer could be reused for one more growth.
By executing this it’s possible to generate much more material a lot more quickly and more price efficiently. This process could make bulk amounts of material, as opposed to merely the thin single-layer manner in which it is generally grown.
Freeing the material from the wafer also starts the opportunity of flexible, thin-film electronics made with gallium arsenide or additional high-speed semiconductors. To make devices that can conform but still maintain high performance, that is significant.
In a paper written and published on-line May 20 in the academic journal Nature, the team describes its techniques and displays 3 types of units using gallium arsenide chips produced in multilayer stacks: light devices, high-speed transistors and photo voltaic cells. The authors additionally offer a detailed cost evaluation.
One more benefit associated with the multilayer method is the release from area constraints, particularly crucial for photo voltaic cells. As the levels are removed from the stack, they may be laid out side-by-side on an additional substrate to generate a much bigger surface area, whereas the typical single-layer procedure limits area to the size of the wafer.
For solar panels, you want large area coverage to catch as much sunlight as achievable. In an extreme case we could develop adequate layers to have ten times the area of the traditional.
Next, the group programs to explore more possible item applications and other semiconductor resources which could adapt to multilayer growth.
About the Writer – Shannon Combs contributes articles for the <a href=”http://www.residentialsolarpanels.org/“>residential solar power systems</a> web site, her personal hobby weblog centered on suggestions to assist home owners to save energy with sun power.
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