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How is gallium arsenide used in diodes, lasers, and transistors?

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A labeled diagram of the periodic table entry for arsenic, showing its atomic number 33, symbol As, atomic weight 74.921595, electron configuration, and classification as an other nonmetal. Additional icons indicate arsenic is solid at room temperature, has a rhombohedral crystal structure, and weakly acidic oxides. — arsenic Properties of arsenic.

Gallium arsenide (GaAs) is a synthetic semiconductor compound composed of gallium and arsenic that is highly valued for its specific optical and electrical properties.12

Diodes and Lasers

In light-emitting diodes (LEDs), gallium arsenide is used because it efficiently converts electrical energy into radiation. When forward-biased, electrons injected into the material drop into holes, releasing energy as light. While its characteristic emission is in the infrared spectrum, it is a primary material for optoelectronic applications. Furthermore, semiconductor lasers often utilize layers of gallium arsenide and related compounds like aluminum gallium arsenide to enable high-frequency modulation, essential for technologies like optical fibre communications.123

Transistors

Gallium arsenide is particularly suited for high-frequency and microwave applications, such as cellular telephone systems, due to its high electron mobility—which is five times that of silicon. It is used to manufacture metal-semiconductor field-effect transistors (MESFETs) and advanced heterojunction field-effect transistors, which leverage the material's ability to support high-speed electron flow.4