About the Book
Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 32. Chapters: Aluminium gallium arsenide, Aluminium gallium indium phosphide, Aluminium gallium nitride, Aluminium gallium phosphide, Copper indium gallium selenide, Digallane, Gadolinium gallium garnet, Galinstan, Gallium(II) selenide, Gallium(II) sulfide, Gallium(II) telluride, Gallium(III) bromide, Gallium(III) fluoride, Gallium(III) hydroxide, Gallium(III) iodide, Gallium(III) oxide, Gallium(III) selenide, Gallium(III) telluride, Gallium antimonide, Gallium arsenide phosphide, Gallium halides, Gallium indium arsenide antimonide phosphide, Gallium maltolate, Gallium manganese arsenide, Gallium nitrate, Gallium phosphate, Gallium trichloride, Indium gallium aluminium nitride, Indium gallium arsenide, Indium gallium nitride, Indium gallium phosphide, Lanthanum gallium silicate, Organogallium chemistry, Plutonium-gallium alloy, Triethylgallium, Trimethylgallium, Tris(dimethylamino)gallium dimer, Vanadium-gallium. Excerpt: Gallium manganese arsenide is a magnetic semiconductor. It is based on the world's second favorite semiconductor, GaAs, and as such is readily compatible with existing semiconductor technologies. Differently from other dilute magnetic semiconductors (DMSs), such as the majority of those based on II-VI semiconductors, it is not paramagnetic but ferromagnetic, and hence exhibits hysteretic magnetization behavior. This memory effect is of importance for the creation of persistent devices. In (Ga, Mn)As, the manganese atoms provide a magnetic moment, and each also acts as an acceptor, making it a p-type material. The presence of carriers allows the material to be used for spin-polarized currents. In contrast, many other ferromagnetic DMSs are strongly insulating and so do not possess free carriers. (Ga, Mn)As is therefore a candidate as a spintronic material. Like other DMSs, (Ga, Mn)As is formed by doping a standard semiconductor with magnetic elements. This is done using the growth technique molecular beam epitaxy (MBE), whereby crystal structures can be grown with atom layer precision. In (Ga, Mn)As the manganese substitute into gallium sites in the GaAs crystal and provide a magnetic moment. Because manganese has a low solubility in GaAs, incorporating a sufficiently high concentration for ferromagnetism to be achieved proves challenging. In standard MBE growth, to ensure that a good structural quality is obtained, the temperature the substrate is heated to, known as the growth temperature, is normally high, typically 600 C. However, if a large flux of manganese is used in these conditions, instead of being incorporated, segregation occurs where the manganese accumulate on the surface and form complexes with elemental arsenic atoms. This problem was overcome using the technique of low-temperature MBE. It was found, first in (In, Mn)As and then later used for (Ga, Mn)As, that by utilising non-equilibrium crystal growth techniques larger dopant concentrations could be succ
