Indium arsenide bands

EXAMPLE 4.3 Figure 4.9(a) shows the dependence of the absorption coefficient versus the photon energy for indium arsenide, (a) Determine whether or not InAs is a direct-gap semiconductor, (b) Estimate the band-gap energy, (c) If an InAs sample of 1 mm thickness is illuminated by a laser of 1 W at a wavelength of 2 jam, determine the laser power for the beam after it passes through the sample. Only consider the loss of light by optical absorption. 

The monotonic change in mobility, the low effective mass of the electrons ( 0.05m ), and the linear change in the energy gap with the composition, enable us to suggest that the band structures of indium arsenide and its alloys with cadmium telluride in the region of indium arsenide are similar. 

Indium Arsenide (InAs). Indium arsenide resembles InSb in its band structure, having only a slightly larger energy gap and a smaller spin-orbit splitting of the top of the valence band. The conduction band minimum (Fg) is situated in the center of the Brillouin zone. Near the minimum, E(k) is isotropic but nonparabolic. The valence band shows the usual structure common to all zinc blende-type III-V compounds (Fig. 4.1-116). 

The thermal conductivity of diamond at 300 K is higher than that of any other material, and its thermal expansion coefficient at 300 K is 0.8 x 10". lower than that of Invar (an Fe-Ni alloy). Diamond is a very widc-band gap semiconductor Eg = 5.5 eV), has a high breakdown voltage (I07V cm-1), and its saturation velocity of 2.7 x I01 cm s-1 is considerably greater than that of silicon, gallium arsenide, or indium phosphide. 

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... 

There have been many papers In recent years dealing with the magnetic properties of semiconductors. Such studies are of particular Importance when discussing the band structure and chemical bonding in semiconducting compounds. Indium antimonide and arsenide have been thoroughly studied in this respect ([1-3], etc.). It is of interest to study the solid solutions based on these compounds and, in particular, to examine the nature of the relationship between the susceptibility of the solid solutions and their composition, temperature, and carrier density. 

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