Monday, February 23, 2009
Rutgers University researchers have demonstrated what they claim is the world's first reversible diode. Using a ferroelectric material, the new material formulation was also found to be photovoltaic in a part of the spectrum not covered by conventional solar cells, opening the door to a potential new green energy source. The new material is a member of the perovskite class of crystals and is distinguished by using three negative ions of oxygen that bind to two positive ions of very different atomic sizes. Made from bismuth, iron and oxygen, the reversible diode can alter the direction in which it allows current to pass by switching its ferroelectric polarization.
BOTTOM LINE: A availability of a reversible diode is sure to spur electrical engineers to find useful applications. The ferroelectric material will have to be integrated into someone's CMOS process to be used on conventional chips, which takes time. Discrete devices seem inevitable too. The utility of the material also being photovoltaic in the blue color gamut could help the efficiency of multi-junction solar cells, but this all depends on optimizing and fully characterizing the material, which could take years.
Posted by R. Colin Johnson at 11:17 AM