Rich Essential Properties of Si-Doped Graphene

Carbon atoms could form 3D diamond, ¹ 3D graphites, ² 2D layered graphenes, ^{3 , 4} 1D graphene nanoribbons, ^5–7 1D carbon nanotubes, ^8–10 0D carbon toroids, ^{11 , 12} 0D C₆₀-related fullerenes, ¹³ and 0D carbon onions. ¹⁴ The versatile morphologies directly indicate the peculiar chemical bondings, in which all carbon-created systems possess sp²-bonding surfaces except for the sp³ bondings in diamond. Specifically, the few- and multi-layer graphene systems have been manufactured using the various methods ^{15 , 16} since the first experimental observation in 2004 by mechanical exfoliation. Up to now, they have clearly exhibited plenty of remarkable fundamental properties due to the hexagonal symmetry, the nanoscaled thickness, and the distinct stacking configurations, such as semiconducting and semimetallic behaviors, ^{17 , 18} anomalous quantum Hall effects, ¹⁹ diverse magnetic quantizations, ^20–23 rich coulomb excitations and decays, ^24–28 different magneto-optical selection rules, ^29–31 the exceedingly high mobility of charge carriers, ^{32 , 33} and the largest Young’s modulus of materials ever tested. ³⁴ To induce the novel phenomena and extend the potential applications, the electronic properties could be easily modulated by the layer number, ^{35 , 36} stacking configuration, ^37–39 mechanical strain, ^{40 , 41} sliding, ⁴² electric and magnetic field, ^{43 , 44} chemisorption, ^45–48 and direct doping. ^49–51 This book chapter focuses on the latter two factors.