Gallium laser diode

Gallium(III) azide, 72 360 Gallium-based laser diodes, 72 349 Gallium chalcogenides, 72 359 Gallium compounds, 72 344, 355-361 with ammonia, 72 357-358 with phosphorus, arsenic, and antimony, 72 360... 

The gallium aluminum arsenide (GaAlAs) and indium phosphide (InP) laser diodes are among the most used NIR excitation sources (Figure 7.4). These diodes are... 

In a laser diode, population inversion of charge carriers in a semiconductor is achieved by a very high electric field across a pn junction in gallium arsenide. Most laser diodes operate at red and near-infrared wavelengths (680-1 550 nm). 

Gallium-based laser diodes have also lost some of the market in telecommunications to indium-based devices. Optical fiber systems moved to the use of longer wavelengths for long distance networks. 

Gallium and indium phosphides, arsenides and anti-monides have important applications in the semiconductor industry (see Sections 5.9 and 27.6 Boxes 13.3 and 18.4). They are used as transistor materials and in light-emitting diodes (LEDs) in, for example, pocket calculators the colour of the light emitted depends on the band gap. Figure 12.3 shows that, in 2001, the US used 37% of the gallium produced worldwide. Almost all of this was used in the form of GaAs 34% went into LEDs, laser diodes, photodetectors and solar cells, while 65% found application... 

In materials science we often divide materials into distinct classes. The primary classes of solid materials are ceramics, metals, and polymers. This classification is based on the types of atoms involved and the bonding between them. The other widely recognized classes are semiconductors and composites. Composites are combinations of more than one material and often involve ceramics, such as fiberglass. Semiconductors are materials with electrical conductivities that are very sensitive to minute amounts of impurities. As we will see later, most materials that are semiconductors are actually ceramics, for example, gallium nitride, the blue-green laser diode material. 

In recent years, semiconductor fabrication techniques have progressed to an extent that permits the construction of highly complex integrated devices such as the distributed Bragg-reflector (DBR) laser diode shown in Figure 7-9. This device contains a gallium arsenide /in-junction diode that produces infrared radiation at about 975 nm. In addition, a stripe of material... 

Gallium nitride laser diodes produce radiation directly in the blue, green, and yellow region of the... 

Fig. 12. Details of an aluminum gallium arsenide semiconductor diode laser.

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