June 25, 2015

STANFORD RESEARCHERS STRETCH A THIN CRYSTAL TO GET BETTER SOLAR CELLS




Crystalline semiconductors such as silicon can catch photons and convert their energy into electron flows. New research shows that a little stretching could give one of silicon's lesser-known cousins its own place in the sun.

(June 25, 2015)  Nature loves crystals. Salt, snowflakes and quartz are three examples of crystals – materials characterized by the lattice-like arrangement of their atoms and molecules.

Industry loves crystals, too. Electronics are based on a special family of crystals known as semiconductors, most famously silicon.

To make semiconductors useful, engineers must tweak their crystalline lattice in subtle ways to start and stop the flow of electrons.

Semiconductor engineers must know precisely how much energy it takes to move electrons in a crystal lattice.

This energy measure is the band gap. Semiconductor materials such as silicon, gallium arsenide and germanium each have a band gap unique to their crystalline lattice. This energy measure helps determine which material is best for which electronic task.