Gallium arsenide properties

Gallium arsenide is epitaxially deposited on a silicon substrate and the resulting composite combines the mechanical and thermal properties of silicon with the photonic capabilities and fast electronics of gallium arsenide. 

Silicon is not as prominent a material in optoelectronics as it is in purely electronic applications, since its optical properties are limited. Yet it finds use as a photodetector with a response time in the nanosecond range and a spectral response band from 0.4 to 1.1 im, which matches the 0.905 im photoemission line of gallium arsenide. Silicon is transparent beyond 1.1 im and experiments have shown that a red light can be produced by shining an unfocused green laser beam on a specially prepared ultrathin crystal-silicon slice.CVD may prove useful in preparing such a material. 

The predictions made by Mendeleev provide an excellent example of how a scientific theory allows far-reaching predictions of as-yet-undiscovered phenomena. Today s chemists still use the periodic table as a predictive tool. For example, modem semiconductor materials such as gallium arsenide were developed in part by predicting that elements in the appropriate rows and columns of the periodic table should have the desired properties. At present, scientists seeking to develop new superconducting materials rely on the periodic table to identify elements that are most likely to confer superconductivity. 

G.R. Antell, Gallium Arsenide Transistors T.L. Tansley, Heterojunction Properties... 

Duan, X. Wang, J. Lieber, C. M. 2000. Synthesis and optical properties of gallium arsenide nanowires. Appl. Phys. Lett. 76 1116-1118. 

Single crystal silicon (sc-Si), polyciystalline silicon (p-Si), and amorphous silicon (a-Si) can all be used to make solar cells, with fabrication cost and device photoconversion efficiencies decreasing as one moves from single-crystal to amorphous materials. Various properties of these materials are summarized in Table 8.1. Other relatively common solar cell materials include gallium arsenide (GaAs), copper indiirm diselenide (CIS), copper indium-gallium... 

Gallium arsenide exhibits semiconductor properties. It is used in transistors, lasers, solar cells and various high-speed microcircuits. 

Very broadly speaking, two situations have to be considered in explaining devices such as those we have mentioned. In the first, which is relevant to the ruby laser and to phosphors for fluorescent lights, the light is emitted by an impurity ion in a host lattice. We are concerned here with what is essentially an atomic spectrum modified by the lattice. In the second case, which applies to LEDs and the gallium arsenide laser, the optical properties of the delocalised electrons in the bulk solid are important. 

Gallium arsenide and silicon transistors each have their own specific advantages. ClaAs transistors switch faster than Si transistors and they also emit near-infrared and visible light, a property of value when both optical and electrical functions are combined in one chip. In many other respects, the GaAs devices are inferior to their silicon counterparts. Researchers have recently found how to effect epitaxial growth of crystalline GaAs layers... 

Blakemone, J.S. Gallium Arsenide, Springer-Verlag, Inc.. New York. NY, 1998. Burch. A, Pure Metals Properties, A Scientific and Technical Handbook, ASM International, Materials Park, OH, 1999. 

A major advantage of the gallium arsenide (GaAs) laser is that it has the electron distribution of a semiconductor The main difference between electrons in semiconductors and electrons in other laser media is that in semiconductors all of the electrons occupy and thus share the entire crystal volume. Although all semiconductors possess this property, not all of them can be used as lasers. See Fig. 4. 

Property Gallium arsenide Lithium niobate EO polymers... 

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