I was contacted by Shannon Coombs who offered to send an article she had written on the usage of gallium arsenide in solar panels. The information appears to be accurate to me based on my web research. The nature.com reference checks out. Here's the full article:
------------------------------------------------------------------------------------------------
Title: College of Illinois Scientists Provide Us Little Known Ways to Produce More Effective Pv panels
Although silicon is actually the market common semiconductor in many electrical devices, including the photovoltaic cells that solar panels utilize to transform sunshine into energy, it is hardly the most efficient product available. For instance, the semiconductor gallium arsenide and connected compound semiconductors provide close to twice the effectiveness as silicon in solar units, but they are rarely used in utility-scale applications because of their excessive production cost.
University. of Illinois. (
http://illinois.edu/) teachers J. Rogers and X. Li discovered lower-cost techniques to create thin films of gallium arsenide that also made possible flexibility in the kinds of units they can be integrated into.
If you may lower significantly the expense of gallium arsenide and some other compound semiconductors, then you can increase their range of applications.
Usually, gallium arsenide is deposited in a individual thin layer on a little wafer. Either the ideal device is made directly on the wafer, or the semiconductor-coated wafer is break up into chips of the ideal size. The Illinois group decided to put in numerous layers of the material on a simple wafer, making a layered, “pancake” stack of gallium arsenide thin films.
If you grow ten layers in 1 growth, you simply have to load the wafer one time. If you do this in ten growths, loading and unloading with temp ramp-up and ramp-down take a lot of time. If you consider what is necessary for each growth – the equipment, the planning, the time, the workers – the overhead saving this method provides is a substantial price decrease.
After that the experts individually peel off the layers and transfer them. To accomplish 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 levels of aluminum arsenide, freeing the single small sheets of gallium arsenide. A soft stamp-like system picks up the layers, one at a time from the top down, for transfer to one other substrate – glass, plastic material or silicon, based on the application. Then the wafer can be used again for one more growth.
By executing this it's possible to produce a lot more material a lot more fast and a lot more cost effectively. This process could produce bulk amounts of material, as compared to just the thin single-layer way in which it is generally grown.
Freeing the material from the wafer additionally starts the opportunity of flexible, thin-film electronics produced with gallium arsenide or other high-speed semiconductors. To make products that can conform but still retain higher efficiency, which is considerable.
In a document published online May twenty in the journal Nature (
http://www.nature.com/), the group describes its techniques and shows three kinds of products utilizing gallium arsenide chips made in multilayer stacks: light products, high-speed transistors and solar cells. The creators also offer a comprehensive price comparison.
One more advantage associated with the multilayer technique is the release from area constraints, especially crucial for solar cells. As the levels are removed from the stack, they may be laid out side-by-side on another substrate in order to generate a much larger surface area, whereas the standard single-layer process restricts area to the size of the wafer.
For solar panels, you want big area coverage to get as much sunlight as possible. In an extreme situation we could increase sufficient layers to have 10 times the area of the traditional.
After that, the team programs to investigate more possible device applications and other semiconductor resources that could adapt to multilayer growth.
About the Source - Shannon Combs writes for the
http://www.residentialsolarpanels.org web log, her personal hobby website centered on points to help home owners to save energy with solar power.
Photos:
http://www.residentialsolarpanels.org/t ... _solar.jpg
http://www.residentialsolarpanels.org/s ... senium.jpg
Complete Bio Photo of the Author
http://www.residentialsolarpanels.org/about
http://www.residentialsolarpanels.org/f ... hannon.jpg