Doping, of semiconductors

The gas-phase decomposition of beryllocenes has been examined for the doping of semiconductor materials and in the preparation of thin metal films. Molecular-beam expitaxy has been used with (MeC5H4)2Be to dope InP semiconductors only a small amount of carbon is found in the doped films.54 Beryllocene 9 has been explored as a precursor for coating capsules with beryllium metal for use as targets in experiments with inertial confinement fusion.55... 

For a background introduction to the doping of semiconductors, try the fun Website Britney Spears guide to semiconductor physics at http //britneyspears.acAasers.htm, which is actually quite good in parts. 

F. Schubert, Delta-Doping of Semiconductors Electronic, Optical, and Structural Properties... 

The study of metals and metal surfaces is rapidly gaining general interest, mainly because of its importance in industrial research. Semiconductors 136> and especially the doping of semiconductors, S8> are of prime interest. Studies of oxydation states were for instance carried out for W—V—O-phases 122) or for a series of carbides 123>. An example is shown in Fig. 10, where the state of the niobium and nitrogen present in very low concentrations in steel, had to be detected. 

The spectacular success of the semiconductor industry is based on the production of materials selectively designed for specialized applications in electronic and optical devices. By carefully controlled doping of semiconductors with selected impurities—electron donors or electron acceptors—the conductivity and other properties can be modulated with great precision. Fig. 12.8 shows schematically how doped semiconductors work. In an intrinsic semiconductor (a), conducting electron-hole pairs can only by produced by thermal or photoexcitation across the band gap. In (b), addition of a small concentration of an electron donor creates an impurity band just below the conduction band. Electrons can then Jump across a much-reduced gap to the conduction band and act as negatively-charged current carriers. This produces a n-type semiconductor. In (c), an electron acceptor creates an empty impurity band just above the valence band. In this case electrons can jump from the valence band to leave positive holes. These can also conduct electricity, since electrons falling into positive holes create new holes, a sequence... 

Doping of optical materials Doping of semiconductors Formation of non-equilibrium alloys Corrosion of materials ... 

The classical doping of semiconductors shows that a FA can replace an atom of the crystal at a regular lattice site. In covalent or partially covalent crystals, the main parameters which must be considered for the possible location of a FA on a substitutional site are its ability to form chemical bonds with its neighbours and the strengths of these bonds. When a crystal is made... 

Homogeneous doping of semiconductor particles with a small amount of metal ions such as Fe " and V " prolongs the electron-electron-hole separation and hence increases the photocatalytic efficiency [46,47]. However, doping of Ti02 with metal ions such as Cr + and Sb + creates electron acceptor and donor centers that accelerate the charge recombination—an undesirable result for photocatalysis [48-50]. 

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