Lasers, solid-state light-emitting diodes LEDs

One application of modem solid-state electronic devices is semiconductor materials that convert electrical energy into light. These light-emitting diodes (LEDs) are used for visual displays and solid-state lasers. Many indicator lights are LEDs, and diode lasers read compact discs in a CD player. The field of diode lasers is expanding particularly rapidly, driven by such applications as fiber optic telephone transmission. 

GaN is a wide band gap semiconductor (Eg = 3.4 eV) of considerable technological interest. Light-emitting diodes (LEDs) and laser diodes based on GaN and its alloys of either In or A1 have been successfully commercialized for some time. GaN remains a topic of intense interest, and current research primarily focuses on creating more efficient green and red LEDs and laser diodes for solid state lighting and other applications. 

Semiconductor materials are the basis of solid-state electronics devices, such as transistors, light-emitting diodes (LEDs), and laser diodes. A CD player, for example, uses transistors for its electronic circuits, as well as a laser diode to read a compact disc. 

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