June 1, 2009
Strained nanowires promise cheaper
Put nanowires under strain and you've
got a way to lower the cost of silicon solar cells.
A computer model shows that a silicon nanowire that has a
section under strain, meaning its silicon atoms are forced slightly
out of their normal alignment, can channel electrons into a circuit
just like layers of different semiconductor materials do.
When photons produce electrons in solar cells, the electrons
and the holes they leave behind are separated and fed into opposite
ends of an electric circuit. This is usually accomplished in high-performance
crystalline silicon solar cells by two layers of silicon. One layer
is doped, or infused with atoms of another material, to be electrically
positive. The other layer is doped to be negative.
Strained silicon nanowires separate electrons and holes simply
by the wires' small size and the strained crystal structure. If the
silicon nanowires can be readily mass-produced, they could lower the
cost of silicon solar cells because they don't need doping and they
can be made from lower-grade silicon.
via Strain in Silicon Nanowires
Nano Letters, published online May 22, 2009
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June 1, 2009
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