
116 Solid-State Light Sources
The following list is representative of compounds that with the appropriate
addition of materials (doping) and the connection of the p-type and n-type semi-
conductors created, result in the emission of radiation after the ow of electricity.
A general rule is that the energy difference increases (wavelength of emission
decreases) with increasing aluminum (Al) concentration and decreases with
increasing indium (In) concentration.
AlGaAs—Red and infrared
AlGaP—Green
AlGaInP—High brightness, orange-red, orange, yellow, and green
GaAsP—Red, orange-red, orange, and yellow
GaP—Red, yellow, and green
GaN—Green and blue
InGa