Group IV semiconductors

The group IV semiconductor materials are fourfold coordinated covalent solids from elements in column IV of tire periodic table. The elemental semiconductors are diamond, silicon and gennanium. They crystallize in tire diamond lattice. 

In most metals the electron behaves as a particle having approximately the same mass as the electron in free space. In the Group IV semiconductors, dris is usually not the case, and the effective mass of electrons can be substantially different from that of the electron in free space. The electronic sUmcture of Si and Ge utilizes hybrid orbitals for all of the valence elecU ons and all electron spins are paired within this structure. Electrons may be drermally separated from the elecU on population in dris bond structure, which is given the name the valence band, and become conduction elecU ons, creating at dre same time... 

Another source of departure from stoichiometry occurs when cations are reduced, as for example in tire reduction of zinc oxide to yield an oxygen-defective oxide. The zinc atoms which are formed in tlris process dissolve in the lattice, Zn+ ions entering interstitial sites and the coiTesponding number of electrons being released from these dissolved atoms in much the same manner as was found when phosphorus was dissolved in the Group IV semiconductors. The Kroger-Viirk representation of dris reduction is... 

Bent, S. F. Organic functionalization of group IV semiconductor surfaces principles, examples, applications, and prospects. Surface Science 500, 879-903 (2002). 

The tetrahedral open network is a specific characteristic not only of water and silica but also of covalent systems such as Si and Ge (group IV semiconductors) [254, 255], These substances share many characteristics with water, such as... 

For the elementary group IV semiconductor (001) surfaces there are in principle 3 plausible adsorption sites for ad-dimers on-top of the substrate rows with the dimer bond of the ad-dimer either parallel (A configuration) or perpendicular (B configuration) to the substrate dimer bonds and a third adsorption site in the trough with the dimer bond of the ad-dimer aligned parallel to the substrate dimer bonds (C configuration). For Ge/Ge(0 01) and Ge/Si(0 01) ad-dimers is also some intermediate configuration on-top of the substrate dimer rows labeled A/B. Whether this is really a stable adsorption site or just due to the fact that the ad-dimer rapidly rotates back and forth from A to B and vice versa is not yet settled. 

Bent SF (2002) Organic Functionalization of Group IV Semiconductor Surfaces Principle, Examples, Applications, and Prospects, Surf Sci 500 879-903... 

In group-IV semiconductors, donors like P and As and acceptors like Al are monoisotopic, but others show an isotopic distribution (see appendix D). Beyond EMT, calculations of the isotopic splitting of the ground state of... 

Table 8.7. Energies and symmetries of the stress-split sublevels of a Ts level of an acceptor with Ta symmetry in a group-IV semiconductor (after [32])...

The plastically extruded layer around indentations is observed more often in Ge than in Si [38, 121]. Such a layer (Fig. 26) is believed to represent a squeezed-out ductile metallic phase that forms under the indenter during the loading stage. In general, although much less effort was put into the indentation studies of Ge as compared to Si, it is acknowledged in the literature that the behavior of both group IV semiconductors is very similar. 

An analysis was made of the published experimental and calculated values of the theimochemical constants of gallium phosphide (the standard entropy and the specific heat, the enthalpy, and the free energy of formation of diis compound) and of the equilibrium constants and vapor pressure of phosphorus. Approximate methods were used to calculate the remaining constants the specific heat was found by the Landiya method and the standard entropy was deduced from the Eastman equation and by summing the entropies of elemental group IV semiconductors. 

TABLE 1. Combinations of Elemental Group IV Semiconductors Simulating Compounds... 

TABLE 2. Heats of Atomization (kcal/mole) of Elements A and B, and of Elemental Group IV Semiconductors... 

Thurmond and Frosch [15] established that the values of the standard entropies of A B compounds are in very good agreement with the values calculated by summing the entropies of the corresponding elemental group IV semiconductors. 

Table 6 lists the equations for the specific heats of elemental group IV semiconductors, which were used to calculate the specific heats of A % compounds. 

TABLE 6. Equations for Specific Heats of Elemental Group IV Semiconductors [22]... 

Table 7 gives our estimates of the specific heats of A B compounds. The data presented in this table confirm that the specific heats of these compounds can be calculated by summing the specific heats of elemental group IV semiconductors. Such summation yields results which are in good agp eement with the experimental values. 

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