Impurity-doping effect

Hakkinen H, Abbet W, Sanchez A, Heiz U, Landman U (2003) Structural, electronic, and impurity-doping effects in nanoscale chemistry Supported gold nanoclusters. Angew Chem Int Edit 42 1297... 

Impurity-doping Effects Finally, we address the possibility of enhancing the... 

The computer simulation has been employed to clarify in detail impurity-doping effects. A molecular-cluster approach was extensively adopted, see references in [718). These cluster calculations have never led to unifying conclusions regarding the effects of doping on the electronic states due to the influence of danghng bonds. 

Intentional impurities, doping After the comments previously reported on impurity effects and on the path towards higher and higher purity, a few remarks may be noteworthy on intentional addition of Impurities . To underline this point we quote... 

Systematic investigations on the dependence of the PPC properties on different growth conditions are still needed to elucidate the nature of the deep level defects which are responsible for PPC. Needless to say, the future development of GaN devices depends critically on the improvements in impurity doping, which would rely heavily on the full understanding of the physics of doped impurities. For many device applications, it is important to eliminate (or minimise) effects of deep level impurities through improved crystal growth processes and device designs. 

The formation of CO2 is then measured for the mixed cluster samples and compared to the formation on pure Au clusters. Fig. 1.76 shows the one cycle TPR spectra for the clean MgO and gold films as well as for selected cluster sizes, which are discussed in detail below for understanding the impurity doping and the size effects. Whereas the pure gold tetramer is inert, the strontium-doped AusSr cluster produces CO2 at 250 and 500 K. These... 

Core-polarisation and conduction-electron polarisation effects can be studied as can exchange polarisation of diamagnetic atoms in magnetic hosts. The lattice dynamics of the metal lattice are examined via the temperature dependence of the /-factor. Many metals approximate closely to the Debye model, and a Debye temperature has some significance. Impurity doping can... 

Another aspect of the impurity doping which will be common in mineral particles is illustrated by the effect of Nb(V) on anatase. This ion substitutes isomorphical-ly for Ti(IV) and as an n dopant creates a Shottky barrier at the interface. This assists injection of an electron from a reducing solute into the conduction band (1J[). The flat band is also shifted cathodically. It has recently been claimed that the relative inefficiency of haematite as a photoanode is a function of low mobility of carriers and that this problem may be... 

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