Semiconductor-diode light sources

Electroluminescence can occur as a result of the application of a direct current at a low voltage to a suitably doped crystal containing a p-n junction. It has become apparent in recent years that in certain materials (such as gallium arsenide) and under certain conditions, the efficiency of conversion of electric energy into light can be remarkably high. Since these semiconductor light sources operate at low voltages and low currents and can be made very small, they appear attractive for use in small optical displays. Because they can be switched very rapidly and have fairly monochromatic emission properties, their applications for data transmission are also promising.