23. Gallium Arsenide

The history of gallium arsenide is complicated because the technology required to produce GaAs devices has been fraught with problems associated with the material itself and with difficulties in its fabrication. Thus, for many years, GaAs was labelled as “the semiconductor of the future, and it will always be that way.” Recently, however, advances in compact-disc (CD) technology, fibre-optic communications and mobile telephony have boosted investment in GaAs research and development. Consequently, there have been advances in materials and fabrication technology and, as a result, GaAs devices now enjoy stable niche markets.

The specialised uses for GaAs in high-frequency and optoelectronic applications result from the physical processes of electron motion that allow high-speed and efficient light emission to take place. In this review, these advanced devices are shown to result from the physical properties of GaAs as a semiconducting material, the controlled growth of GaAs and its alloys and the subsequent fabrication into devices.

Extensive use is made of chapters from “Properties of Gallium Arsenide, 3rd edition” which I edited with the help of Prof. G. E. Stillman [23.1]. This book was written to reflect virtually all aspects of GaAs and its devices within a readable text. I believe that we succeeded in that aim and I make no apologies in referring to it. Readers who need specialised data, but not necessarily within an explanatory text, should refer to the Landolt-Börnstein, group III (condensed matter) data collection [23.2,3]. The sub-volumes A1α (lattice properties) and A2α (impurities and defects) within volume 41 are rich sources of data for all III–V compounds. Although there are no better sources than the original research papers, I have referred to textbooks where possible. This is because the presentation and discussion of scientific data is often clearer than in the original text, and these books are more accessible to students.

Gallium arsenide (GaAs) is one of the most useful of the III–V semiconductors. In this chapter, the properties of GaAs are described and the ways in which these are exploited in devices are explained. The limitations of this material are presented in terms of both its physical and its electronic properties.