Disorder, clustering, and localization effects in amorphous carbon

2020-02-15 00:54:29

amorphous electron density disorder spin

责任者: Carey, J.D.;Silva, S.R.P. 单位: Nanoelectron. Centre, Univ. of Surrey, Guildford, UK 来源出处: Physical Review B (Condensed Matter and Materials Physics)(Phys. Rev., B, Condens, Matter Mater. Phys. (USA)),2004/12/15,70(23):235417-1 摘要: The nanostructure of amorphous carbon thin films is described in terms of a disordered nanometer-sized conductive sp2 phase embedded in an electrically insulating sp3 matrix. It is shown that the degree of clustering and disorder within the sp2 phase plays a determining role in the electronic properties of these films. Clustering of the sp2 phase is shown to be important in explaining several experimental results including the reduction of the electron spin resonance linewidth with increasing spin density and the dispersion associated with the width of the Raman active G band. The influence of structural disorder, associated with sp2 clusters of similar size, and topological disorder, due to undistorted clusters of different sizes, on both spin density and Raman measurements, is discussed. An extension of this description to intercluster interactions to explain some of the electrical transport and electron field emission behavior is also presented 关键词: amorphous semiconductors;band structure;carbon;electron field emission;localised states;nanostructured materials;paramagnetic resonance;Raman spectra;semiconductor thin films;spectral line breadth;spin density waves;disorder effect;clustering effect;localization effect;amorphous carbon thin film;nanometer-sized conductive phase;electrically insulating matrix;electron spin resonance linewidth;spin density;Raman measurements;intercluster interactions;electronic transport;electron field emission behavior;C