While silicon is actually the industry standard semiconductor in almost all electric units, which includes the pv cells that pv panels utilize to convert sunshine into energy, it is hardly the most cost-efficient material readily available. For example, the semiconductor gallium arsenide and associated compound semiconductors provide practically two times the performance as silicon in solar products, however they are rarely utilized in utility-scale applications because of their excessive manufacturing cost.
U. of I. (http://illinois.edu/) teachers J. Rogers and X. Li explored lower-cost ways to manufacture thin films of gallium arsenide that also made possible flexibility in the kinds of products they could be included into.
If you can minimize significantly the price of gallium arsenide and other compound semiconductors, then you could increase their variety of applications.
Generally, gallium arsenide is deposited in a individual thin layer on a small wafer. Either the ideal device is made right on the wafer, or the semiconductor-coated wafer is break up into chips of the preferred dimension. The Illinois team decided to put in multiple layers of the material on a simple wafer, creating a layered, “pancake” stack of gallium arsenide thin films.
If you increase 10 levels in a single growth, you simply have to fill the wafer one time. If you do this in 10 growths, loading and unloading with temperature ramp-up and ramp-down take a lot of time. If you consider exactly what is needed for every growth — the machine, the preparation, the period, the workers — the overhead saving this approach presents is a substantial price decrease.
Following the experts separately peel off the levels and transport them. To achieve this, the stacks swap levels of aluminum arsenide with the gallium arsenide. Bathing the stacks in a solution of acid and an oxidizing agent dissolves the levels of aluminum arsenide, freeing the individual small sheets of gallium arsenide. A soft stamp-like system picks up the layers, just one at a time from the top down, for transfer to one other substrate — glass, plastic material or silicon, depending on the application. Next the wafer may be reused for one more growth.
By performing this it’s possible to create much more material a lot more rapidly and a lot more price effectively. This process could make bulk amounts of material, as compared to simply the thin single-layer way in which it is usually grown.
Freeing the material from the wafer additionally starts the possibility of flexible, thin-film electronics produced with gallium arsenide or many other high-speed semiconductors. To make units that could conform but still retain high performance, which is considerable.
In a paper written and published on-line May 20 in the magazine Nature (http://www.nature.com/), the team details its methods and displays 3 kinds of units utilizing gallium arsenide chips manufactured in multilayer stacks: light units, high-speed transistors and photo voltaic cells. The creators additionally offer a detailed cost evaluation.
Another benefit of the multilayer approach is the release from area constraints, particularly important for photo voltaic cells. As the layers are removed from the stack, they may be laid out side-by-side on another substrate in order to create a significantly greater surface area, whereas the standard single-layer procedure confines area to the size of the wafer.
For photovoltaics, you need big area coverage to get as much sunshine as achievable. In an extreme case we may grow enough levels to have 10 times the area of the traditional.
After that, the team plans to explore more potential item applications and additional semiconductor resources which could adapt to multilayer growth.
About the Article writer – Shannon Combs publishes articles for the residential solar power shingles web site, her personal hobby blog based on suggestions to aid home owners to conserve energy with solar power.