Electron-doping, systematics

In this paper we present a comprehensive first-principles study of the structural, electronic and optical properties of undoped and doped Si nanosystems. The aim is to investigate, in a systematic way, their structural, electronic and stability properties as a function of dimensionality and size, as well as pointing out the main changes induced by the nanostructure excitation. A comparison between the results obtained using different Density Functional Theory based methods will be presented. We will report results concerning two-dimensional, one-dimensional and zero-dimensional systems. In particular the absorption and emission spectra and the effects induced by the creation of an electron-hole pair are calculated and discussed in detail, including many-body effects. 

The local lattice instability by the hole-doping has been smdied by the molecular orbital cluster method [15]. In this method a part of a solid, cluster , is embedded in a model potential that mimics the crystal environment and the molecular orbital calculation is only performed on the cluster. The advantage of this method is that strong-electron correlation is systematically handled. However, the cluster size is rather limited, thus, a care must be taken whether it really reflects the bulk property. 

As intensive studies on the ECPs have been carried out for almost 30 years, a vast knowledge of the methods of preparation and the physico-chemical properties of these materials has accumulated [5-17]. The electrochemistry ofthe ECPs has been systematically and repeatedly reviewed, covering many different and important topics such as electrosynthesis, the elucidation of mechanisms and kinetics of the doping processes in ECPs, the establishment and utilization of structure-property relationships, as well as a great variety of their applications as novel electrochemical systems, and so forth [18-23]. In this chapter, a classification is proposed for electroactive polymers and ion-insertion inorganic hosts, emphasizing the unique feature of ECPs as mixed electronic-ionic conductors. The analysis of thermodynamic and kinetic properties of ECP electrodes presented here is based on a combined consideration of the potential-dependent differential capacitance of the electrode, chemical diffusion coefficients, and the partial conductivities of related electronic and ionic charge carriers. 

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