Despite the fact that silicon is the industry common semiconductor in most electric units, including the pv cells that sun panels use to convert sun rays into energy, it is hardly the most effective material on the market. For example, the semiconductor gallium arsenide and similar substance semiconductors offer nearly 2 times the performance as silicon
Solar Arsenium
in photo voltaic products, yet they are rarely used in utility-scale applications mainly because of their high construction value.
University. of I. (http://illinois.edu/) teachers J. Rogers and X. Li researched lower-cost ways to produce thin films of gallium arsenide that also granted usefulness in the kinds of products they could be incorporated into.
If you could lower considerably the price of gallium arsenide and other compound semiconductors, then you can expand their own variety of applications.
Generally, gallium arsenide is deposited in a individual thin layer on a little wafer. Either the needed unit is produced right on the wafer, or the semiconductor-coated wafer is cut up into chips of the preferred dimension. The Illinois group decided to deposit several levels of the material on a simple wafer, creating a layered, “pancake” stack of gallium arsenide thin films.
If you increase ten layers in one growth, you simply have to fill the wafer 1 time. If you do this in 10 growths, loading and unloading with temperature ramp-up as well as ramp-down take a lot of time. If you take into account what is necessary for each growth – the equipment, the research, the time, the people – the overhead saving this technique presents is a important expense reduction.
Thin Film Solar
After that the researchers individually peel off the levels and shift them. To achieve this, the stacks swap levels 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 individual small sheets of gallium arsenide. A soft stamp-like device picks up the levels, just one at a time from the top down, for exchange to another substrate – glass, plastic or silicon, depending on the application. After that the wafer could be used again for an additional growth.
By executing this it’s possible to produce significantly more material more fast and a lot more cost efficiently. This process could create mass amounts of material, as compared to merely the thin single-layer manner in which it is typically grown.
Freeing the material from the wafer also starts the opportunity of flexible, thin-film electronics produced with gallium arsenide or other high-speed semiconductors. To make products which may conform but still retain higher efficiency, that is considerable.
In a paper released online May 20 in the journal Nature (http://www.nature.com/), the team details its methods and demonstrates 3 types of units using gallium arsenide chips manufactured in multilayer stacks: light units, high-speed transistors and photo voltaic cells. The creators additionally offer a comprehensive price comparability.
Another advantage of the multilayer method is the release from area constraints, especially essential for solar cells. As the levels are removed from the stack, they can be laid out side-by-side on an additional substrate in order to produce a significantly greater surface area, whereas the standard single-layer process limits area to the dimension of the wafer.
For photovoltaics, you want big area coverage to get as much sunlight as possible. In an extreme case we might grow sufficient levels to have 10 times the area of the traditional.
Shannon
After that, the group plans to investigate more possible product applications and additional semiconductor materials which could adapt to multilayer growth.
About the Publisher – Shannon Combs shares knowledge for the residential solar power products web log, her personal hobby weblog based on guidelines to help home owners to conserve energy with sun power.