Compound zinc blende materials

Most surfaces of compound semiconductors are polar, that is, the number of anions and cations per surface unit cell is not balanced. While for the zinc blende materials there is only one nonpolar exception, the (110) face, for the wurtzite structures, there are two nonpolar surfaces, the m-plane (1100) and a-plane (1120) [98]. In wurtzite materials, a (110) surface does not exist because of the different crystal structure. 

An attempt was made in this paper to sketch the behavior of elemental semiconductors (with the diamond-type structure) and of the IH-V compounds (with the zinc blende strut ture) in aqueous solutions. These covalent materials, in contrast to metals, exhibit properties which sharply reflect their crystalline structure. Although they have already contributed heavily to the understanding of surfaces in general, semiconductors with their extremely high purity, crystalline perfection, and well-defined surfaces are the most promising of materials for surface studies in liquid and in gaseous ambients. 

Recently, Mg and Be compounds have been used in alloys with ZnSe to make blue and green semiconductor lasers. Bulk growth by zone melting and molecular beam epitaxy (MBE) ° has been used. In these cases, good semiconductor material has been obtained dilution with group IIB compounds may be responsible. However, growth of pure MgS in very thin films on ZnSe has been achieved the epitaxial orientation effect of the substrate results in a tetrahedral cubic (sphalerite or zinc-blende) structure. It is likely that improvements in these materials will take place at a rapid rate, driven in part by applications and in part by newer, cleaner synthetic methods. 

Like other zinc-blende type compounds GeSi is an infrared active material. The optical phonon at the F-point is associated with an electric dipole moment which is related to the transverse effective charge e. In terms of ap and its volume derivative (see eq. (49) of Ref. [8]), is given by... 

CdTe, HgS, HgSe and HgTe. Each binary compound (including zinc blende) is an intrinsic semiconductor. The wurtzite lattice is also important in semiconducting materials ZnO, CdSe and InN are examples of compounds adopting this structure. 

In August 1875, Boisbaudran observed a pair of violet lines in the spark spectrum of some material he had separated from zinc blende from the Pierrefitte mine, from which he concluded the presence of a new element. This he named gallium in honour of his native country. Later in the year he obtained a small quantity of the free metal by electrolysis of a solution of gallium hydroxide in caustic potash. It was Mendel eff himself who, in November 1875, suggested the identity of this element with eka- aluminium, and further study of its properties and those of its compounds confirmed this view. 

Thus the zinc blende structure semiconductors can be useful for intrinsic photoconductive detectors. Compounds such as InSb have been used as intrinsic photoconductors [4.20], as well as for photovoltaic detectors, but greater versatility of wavelength response is possible with the Hg j tCd Te alloy system. The Hgi j.Cd,Te alloys have received considerable development effort in recent years and are the most prominent intrinsic photoconductor materials they will be analyzed in this subsection. The development of Hg, Cd Te has concentrated almost entirely on n-type material since it provides high photoconductive gain however, p-type Hg, Cd,(Te crystals may be useful for intrinsic photoconductive detectors also [4.21]. 

The III-V compound semiconductors AlAs and GaAs both have the zinc blende structure and are chemically compatible. Furthermore, as can be seen from Figure 1.17, the stress-free lattice dimensions of the two materials are nearly identical. Another pair of III-V materials having nearly identical lattice dimensions is AlP and GaP. In either of these cases, a thin film of... 

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