International team seeks alternative for solar cell semiconductors

You've probably heard the rare elements used to make semiconductors for solar cells are running out and their prices skyrocketing. Now an international team of scientists and engineers, including researchers from Western Michigan University has demonstrated a new material made from abundant elements can be used instead.

The key is the compound that once was believed to be wrong for the job can be used if it is "tuned." The compound is ZnSnN2---zinc tin nitride. It has been recently synthesized by groups around the world, relying on zinc and tin, metals which are readily available in recycling facilities. It would replace expensive rare materials such as gallium and indium.

Whether the new semiconductor will work as anticipated has to do with something called its band gap, a defining characteristic of semiconductors. It originally was believed band gap for the new compound was too large for it to be used in solar cells. Now researchers have found that they can alter zinc tin nitride, paving the way for this material to be considered for solar cell applications.

"We use a sophisticated crystal growth technique known as molecular beam epitaxy," says Dr. Steve Durbin, professor and chair of electrical and computer engineering at Western Michigan University. “It allows us to control crystal quality by carefully adjusting parameters such as temperature and the ratio of incident atomic (or molecular) beams."

A report on work and that of the rest of the team is found here.  

Source: Western Michigan University
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