Compounds nitrides

III—V nitride compounds suitable for fabricating blue/uv emitters. Also shown is the lattice parameter of various materials proposed as substrates. 

An extensive compilation of the properties of compound semiconductors may be found in the Landolt-Bn mstein reference books (13,14). Various subvolumes in the series cover the properties of elemental. III—V, II—V, and other less common semiconductors. Information may also be found concerning semiconductor technology. Another useful source of information is the EMIS data review series (15). These books describe the properties and technology of GaAs, HgCdTe, InP, AlGaAs, InGaAs, and the III—V nitride compounds. 

Nitrogen Selenide. (Selenium Nitride). See under List of Nitride Compounds in this Vol... 

The small atoms at the center of the first row of the Periodic Table (B, C, N, O, and to a lesser extent Al, Si, and P) can fit into the interstices of aggregates of larger transition metal atoms to form boride, carbide, and nitride compounds. These compounds are both hard and moderately good electronic conductors. Therefore, they are commonly known as hard metals (Schwarzkopf and Kieffer, 1953). 

Rhenium(VI) nitride compounds can be generated by oxidation of rhenium(VI) complexes with chlorine or bromine. The products formed are often unstable and ligand exchange reactions with CP or Br lead to a complex mixture of Re compounds. Oxidation of the rhenium(V) complex [ReN(PPh3)Cl(cpCo PO(OR)2 3)] with Ag(BF4), however, yields [ReN(PPh3)Cl(cpCo- P0(0R)2)3)](BF4) (53) in good yields. ... 

The first mechanism proposes that metal volatilisation causes rupture of molten droplets (as with magnesium), whereas the second considers the production of a volatile oxide such as CO inside materials such as steels that contain an excess of 0.1% carbon. The third mechanism involves the formation of oxy-nitride compounds which decompose at high temperatures, liberating nitrogen (as with titanium). 

No composition or phase change was observed throughout the thickness of the films. This can be explained by the small quantities of metal (films are about 100 nm thick) and by the long reaction times so that the transformation is complete. Nevertheless, the only stoichiometric carbide synthesized is the a-WC form. The same effect was observed for the nitride compounds below 1100 K. Above this temperature, nitrogen... 

No epitaxy could be obtained by reaction of the metal films with reactive gas for short reactions times. This is understandable as the carburization and nitridation reactions progress from the surface of the metal films to the substrate and occur with a change in crystal structure of the film (for instance bcc to hex). So even if the starting metal film is epitaxial, the final carbide or nitride compound could be polycrystalline. For high temperatures and for long time treatments (>15 h), however, perfect epitaxial Y Mo2N films could be obtained on MgO (100).17 In this last case, the crystalline state of the precursor metal film had no effect on the final parallel orientation of the nitride. 

Thermal expansion of a semiconductor depends on its microstructure, i.e. stoichiometry, presence of extended defects, ffee-carrier concentration. For GaAs [24] it was shown that for samples of free-electron concentrations of about 1019 cm"3, the thermal expansion coefficient (TEC) is bigger by about 10% with respect to the semi-insulating samples. Different microstructures of samples examined in various laboratories result in a large scatter of published data even for such well known semiconductors as GaP or GaAs. For group III nitrides, compounds which have been much less examined, the situation is most probably similar, and therefore the TECs shown below should not be treated as universal values for all kinds of nitride samples. It is especially important for interpretation of thermal strains (see Datareview A 1.2) for heteroepitaxial GaN layers on sapphire and SiC. 

TABLE 2 Lattice and elastic stiffness constants ol binary nitride compounds. 

The carbon atom has a lone pair of electrons and is attached to the molybdenum atom by a triple bond. The carbanion has an electronic structure similar to that of the equivalent nitride compound containing a molybdenum-nitrogen triple bond. 

Note This table does not include important nonmetals such as carbon aUotropes or boron nitride compounds These materials will be discussed in subsequent chapters. 

Figure 8.14. MAS NMR spectra of nitride-based ceramic bodies sintered with 10 wt % MgO and related magnesium silicon nitride compounds. A. Si3N4, from MacKenzie and Meinhold (1994), B. (J-sialon, from MacKenzie and Meinhold (1996), C. X-sialon, from MacKenzie et al. (2000), D. Crystalline MgSiNi (upper) and MgAlSiNj (lower), from MacKenzie and Meinhold (1994). All spectra used by permission of the copyright owner.

The glass and boron nitride compounds MgO and AI2O3 in alcoholic solution AI2O3, sodium silicate with Mg (N03)2 and Fe203 ethyl silicate MgFj or AIF, . 

Figure 32 Interconversion of metal nitrosyl and metal nitride compounds via oxo transfer reactions.

For the product synthesized from a 20-wt% VN-diluted sample with preheating at 100 C, it was found that 5-VN was noticeably increased and the amounts of P-V2N and vanadium were substantially decreased. With further increase in the diluent content up to 30 wt%, as shown in Figure 6.5b, the SHS-derived product is essentially an almost fully nitrided compound. 

Due to the PUREX constraint, nitride q>pears to be the best candidate in spite of the enrichment necessity to avoid production. So different nitride compounds are investigated PuN alone, (Pu, X)N solid solution (with X= Zr, Y or Ce), PuN/XN cercer compounds (X= Ce, Al, Zr, Y, Ti) or PuN/Metal cermet (Metal = steel or V). 

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