They can produce photons through a phonon-mediated process known as recombination. The spin-flip Raman laser consists of one in a magnetic field, and 
They can produce photons through a phonon-mediated process known as recombination. The spin-flip Raman laser consists of one in a magnetic field, and when exposed to an energetic photon, electrons in the highest occupied molecular orbital of these materials can be excited to the (*) valence band, leaving behind electron holes. The introduction of electron donators or acceptors can yield the n and p types, which are subdivisions of the extrinsic type of these materials. Cadmium telluride and gallium arsenide are examples of, for 10 points, what materials that possess a small band gap between their valence and conduction bands, allowing for intermediate electrical conductivity?
They can produce photons through a phonon-mediated process known as recombination.
{semiconductor}s