Making Solar Energy

College of Illinois Researchers Indicate Us Little Known Ways to Create More Economical Photovoltaic Panels

While silicon is the industry standard semiconductor in almost all electronic devices, which includes the solar cells that pv panels use to convert sunlight into electricity, it is hardly the most effective material readily available. For instance, the semiconductor gallium arsenide and associated ingredient semiconductors offer practically double the performance as silicon in solar devices, yet they are rarely utilized in utility-scale applications mainly because of their high construction price.

University of Illinois (http://illinois.edu/) teachers J. Rogers and X. Li explored lower-cost techniques to produce thin films of gallium arsenide which also made possible flexibility in the kinds of units they might be integrated into.

If you could minimize considerably the cost of gallium arsenide and other compound semiconductors, then you could expand their range of applications.

Generally, gallium arsenide is transferred in a single thin layer on a small wafer. Either the desired device is created directly on the wafer, or the semiconductor-coated wafer is broken up into chips of the desired size. The Illinois team chose to put in numerous layers of the material on one wafer, making a layered, “pancake” stack of gallium arsenide thin films.

If you grow ten levels in one growth, you simply have to fill the wafer 1 time. If you do this in 10 growths, loading and unloading with temp ramp-up and ramp-down take a lot of time. If you consider what is needed for every growth – the machine, the research, the time, the people – the overhead saving this solution gives is a substantial cost reduction.

Next the researchers independently peel off the levels and transport them. To complete this, the stacks alternate layers 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 individual small sheets of gallium arsenide. A soft stamp-like device picks up the layers, just one at a time from the top down, for exchange to one other substrate – glass, plastic-type or silicon, based on the application. Next the wafer can be used again for an additional growth.

By executing this it’s possible to make considerably more material a lot more rapidly and more price efficient. This process could create mass amounts of material, as opposed to simply the thin single-layer method in which it is usually grown.

Freeing the material from the wafer additionally starts the possibility of flexible, thin-film electronics made with gallium arsenide or different high-speed semiconductors. To make units that can conform but still maintain high efficiency, that is significant.

In a paper written and published online May 20 in the newspaper Nature (http://www.nature.com/), the team describes its techniques and shows 3 types of devices making use of gallium arsenide chips manufactured in multilayer stacks: light units, high-speed transistors and solar cells. The creators additionally provide a comprehensive cost evaluation.

An additional advantage associated with the multilayer approach is the release from area constraints, specifically crucial for solar cells. As the layers are eliminated from the stack, they may be laid out side-by-side on an additional substrate in order to create a much greater surface area, whereas the typical single-layer process limits area to the size of the wafer.

For solar panels, you want big area coverage to catch as much sunshine as possible. In an extreme situation we may grow adequate levels to have ten times the area of the standard.

Up coming, the group plans to explore more possible product applications and additional semiconductor resources that might adapt to multilayer growth.

About the Article author – Shannon Combs is currently writing for the “residential solar power tax credits” web site, her personal hobby website based on points to assist home owners to conserve energy with solar power.

Authors complete Bio & Website: Residential Solar Panels

Technorati Tags: Business, Components, Electronics and Electrical, Gallium arsenide, Semiconductor, Solar cell, Thin film, Wafer (electronics)