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Silicon Defects Corrected

By Stephen Luntz

A method for correcting defects in low-grade silicon could boost the efficiency of commercial photovoltaic panels by 10% in a few years time, further improving solar power’s competitiveness.

The full text of this article can be purchased from Informit.

The manufacture of high-grade silicon is expensive. Specialist uses aside, manufacturers use silicon containing a range of defects. This helps to limit maximum efficiencies for most commercial solar panels to 19%.

“The process by which hydrogen atoms can bind to defects in the silicon, where a silicon atom forms a dangling bond and hydrogen can make it electrically inactive, has been known for some time,” says Prof Stuart Wenham of the School of Photovoltaics and Renewable Energy Engineering at the University of NSW.

However, getting hydrogen atoms to travel through the silicon to the sites of defects and then bond and deactivate them has been a challenge. Hydrogen atoms can be positive, neutral and negative. They move through silicon most easily when neutral, but need to be in an appropriate charge state to fix the defects in the silicon.

While Wenham says “it was once expected to be easy” to control hydrogen’s charge state, this has turned out to be a major obstacle to correcting defects. Now, however, UNSW has patented a method to solve this.

“Our research team has worked out how to control the charge state of hydrogen atoms in silicon,” Wenham says. “We have seen a 10,000 times improvement in the mobility of the hydrogen, and we can control the hydrogen so it chemically bonds to things like defects and contaminants, making these inactive...

The full text of this article can be purchased from Informit.