LED
GaAs is one of the most important direct band gap semiconducting material used in light emitting diodes (LED). With suitable combination of elements, the emission wavelength can be tuned.
GaAs - 870 nm (IR)
GaAs0.6P0.4 - 650 nm (red)
The composition of In and Ga in InGaN can be fine tuned to obtain blue LED which finds significant applications in blue-ray's. In addition to the above a number of semiconducting compounds which emits wavelength from IR to UV ranges could be obtained simply by adjusting the band gap.
Polyacetylene is a conductive polymer used in Polymer LED's. Tris(8-hydroxyquinolinato)aluminium is used in organic LED's.
