University of Illinois Researchers Provide Us Little Known Ways
to Make More Economical Solar Panels
by Shannon Combs

Despite the fact that silicon is actually the market common semiconductor in almost all electric devices, which includes the pv cells that pv panels use to transform sunlight into power, it is not the most cost-efficient material available. For instance, the semiconductor gallium arsenide and connected substance semiconductors give nearly twice the performance as silicon in photo voltaic devices, yet they are rarely employed in utility-scale applications because of their excessive construction value. 

University of Illinois professors J. Rogers and X. Li discovered lower-cost ways to manufacture thin films of gallium arsenide which also granted usefulness in the types of units in which they can be incorporated.  

If you may reduce substantially the price of gallium arsenide and some other compound semiconductors, then you can develop their own range of applications. 

Usually, gallium arsenide is transferred in a individual thin layer on a little wafer. Either the ideal unit is produced right on the wafer, or the semiconductor-coated wafer is cut up into chips of the ideal size. The Illinois team made the decision to put in multiple layers of the material on a single wafer, producing a layered, “pancake” stack of gallium arsenide thin films. 
If you increase ten levels in a single growth, you only have to load the wafer one time. If you do this in 10 growths, loading and unloading with heat range ramp-up and ramp-down take a lot of time. If you consider exactly what is needed for each growth – the machine, the research, the period, the workers – the overhead saving this approach offers is a substantial expense decrease. 
Next the experts independently peel off the layers and transport them. To accomplish this, the stacks alternate levels of aluminum arsenide with the gallium arsenide. Bathing the stacks in a solution of acid and an oxidizing agent dissolves the layers of aluminum arsenide, freeing the single small sheets of gallium arsenide. A soft stamp-like device selects up the levels, just one at a time from the top down, for transfer to another substrate – glass, plastic or silicon, depending on the application. After that the wafer can be reused for another growth. 
By executing this it's possible to produce significantly more material a lot more rapidly and a lot more cost effectively. This process could make bulk amounts of material, as opposed to simply the thin single-layer method in which it is typically grown. 
Freeing the material from the wafer also starts the chance of flexible, thin-film electronics made with gallium arsenide or other high-speed semiconductors. To make devices which could conform but still retain high efficiency, that is considerable.  
Gallium arsenide chips


Shannon Combs writes for the residential solar power installation web log, centered on recommendations to help home owners save energy with sun power.  

In a document released on-line May 20 in the publication Nature (, the group describes its procedures and shows 3 types of devices making use of gallium arsenide chips made in multilayer stacks: light units, high-speed transistors and solar cells. The creators additionally offer a comprehensive price evaluation.

Another advantage of the multilayer approach is the release from area constraints, specifically important for photo voltaic cells. As the layers are eliminated from the stack, they can be laid out side-by-side on an additional substrate to produce a significantly larger surface area, whereas the typical single-layer procedure limits area to the size of the wafer. 

For solar panels, you want big area coverage to catch as much sunlight as possible. In an extreme situation we could increase sufficient levels to have 10 times the area of the conventional. 
Up coming, the group programs to explore more potential device applications and other semiconductor resources that could adapt to multilayer growth. 

Back | Top