Band indium compounds

Band Structures of Indium Compounds. Indium Nitride (InN). The band structure (Fig. 4.1-114) shows a direct gap at F very similar to that of GaN. A low-lying many-valley conduction band leading to an indirect gap has been suggested. 

Preparations of tris-bipyridyl (156, 519) and tris-phenanthroline indium(III) complexes have been described. The d<- d bands fall in the region of the ligand tt <-> tt transitions. The luminescence spectra of the cations are considered to arise from n d transitions (739). Cis-[Ir(phen)2Cl2]Cl is known (156) and has been resolved (104). However, the complex originally claimed as irans-[Ir(phen).2Cl2]Cl-3H20 (156) and shown to react with hydrochloric acid (452) is, in fact, (phen H+)[Ir(phen)Cl4] (104). The compounds [Ir(phen)2X.2]+ [Ir(phen)X4] are known (X = Cl, Br, or I) and the cations probably have cis configurations. 

In 10-2 M HC1, [In(tmpyp)]5+ has bands at 424 nm (e = 390,000), 518 nm (e = 3690), 558 nm (c = 23,200), and 597 nm (e = 4660). The spectrum is similar to that of indium(III)-tetraphenylporphyrin.16 The [In(tmpyp)]5+ is fully water soluble, and rapid acid solvolysis occurs only above 3 M HC1 levels. Refluxing a divalent metal chloride with H2tmpyp in water, and keeping the pH between 3 and 5, is the general method used to prepare the Cu2+, Zn2+, Ni2+, Mn3+, Fe3+, and Co3+ compounds.6 The 642-nm free-base porphyrin band disappears when the incorporation reaction is complete. The high-pH conditions (a) reduce the concentration of unreactive centrally protonated15 porphyrins, (b) minimize the extent of acid catalyzed metalloporphyrin solvolysis reactions,17 and (c) increase the concentration of the often more reactive hydrolyzed metal ion forms.18... 

At room temperature In[CH2(SiMe3)]3 is a colorless pyrophoric liquid. The H NMR spectrum of the compound in benzene (reference 8 7.13) consists of two lines in area ratio 9 2, with the larger methyl line at 8 -1-0.13 and the smaller methylene line at 8 -O.OS.t The IR spectrum of the neat liquid has bands at 2935 (vs), 2885 (s,sh), 1440 (w), 1400 (w), 1350 (w), 1291 (w,sh), 1244 (vs), 920 (s), 825 (vs), 757 (vs), 720 (vs), 692 (s,sh), 580 (m), and 490 (m) cm". The compound can be used to prepare [(trimethylsilyl)methyl]indium halogen compounds by appropriate stoichiometric exchange reactions with InClj, InBrj, and Ini. Properties of many of these organoindium halogen compounds have been reported. The experimental procedure is related to that described for Al(CH2SiMe3)2Br, except that solvents are used for the reactions. 

A solid solution of indium phosphide, InP, and aluminium phosphide, AlP, In t Ali tP is made up. At what value of x will the light emitted by an LED made from this compound just be visible What colour will it be The band gap of InP is 1.27 eV and that of AlP is 2.45 eV. 

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. 

For the development of cheap solar cells, layers of a heavily doped semicon-dnctor like ITO, which may act as a barrier-forming semiconductor, a wide band gap window, and an antireflection coating in the heterostructure [1, 24], attract particular interest. It was shown [25] that the application of vacuumless technologies such as pyrolysis in air for the production of the above-mentioned layers can substantially influence the properties of interfacial layers. The IR spectra of 10283-SiOj -Si heterostructures in solar cells were studied. The 10383 films were produced by thermal decomposition of a complex of the general form L3ln (where L is a ligand). Thermal decomposition of this compound on a heated Si substrate (T = 230-270°C) produces a film of indium sulfide with good adhesion... 

Indium Phosphide (InP). Indium phosphide is a direct-gap semiconductor. The conduction band minimum is situated at F. Higher conduction band minima at L and X have been detected in optical experiments. The X-band minima show no camel s back structure, in contrast to most other III-V compounds with the zinc blende structure. The valence band has the structure common to all zinc blende-type semiconductors (Fig. 4.1-113). 

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). 

Warren and co-workers have reported remarkable data on molten indium dihalides/ " In the solid state these are typical class I compounds, In(I)In(III)X4, but in molten InCl2 the optical band for In(III)---In(I)- In(II) In(II) is found at 17,000 cm" and from In NMR the nuclear relaxation rates above 400°C are interpreted in terms of the mechanism in equation (11) ... 

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