Silicon superlattice

D. Buttard, D. Bellet, andT. Baumbach, X-ray diffraction investigation ofporous silicon superlattices, Thin Solid Films 276, 69, 1996. 

Ruan J, Fauchet PM, Dal Negro L, Cazzanelli M, Pavesi L (2003) Stimulated emission in nano-crystalline silicon superlattices. Appl Phys Lett 83 5479-5481 Shaklee KL, Leheny RF (1971) Direct determination of optical gain in semiconductor crystals. Appl Phys Lett 18 475... 

Zangooie S, Jansson R, Arwin H (1998) Reversible and irreversible control of optical properties of porous silicon superlattices by thermal oxidation, vapor adsorption, and liquid penetration. J Vac Sci Techol A 16(5) 2901-2912... 

Frohnhoff S, Berger MG (1994) Porous silicon superlattices. Adv Mater 6 963-965... 

The first evidence for hypersonic phononic crystal effects was observed in porous silicon superlattices using Brillouin light-scattering experiments (Parsons and Andrews 2009). Comparison between experiment and theory using the Rytov model indicated that the bulk longitudinal phonon branch had been folded. One of the samples exhibited a spectrum consistent with a bandgap of 3.3 GHz for a first gap located at 13.4 GHz. 

Aliev et al. (2010) used acoustic transmission spectroscopy to measure directly the bandgap of an ADBR showing a first-order bandgap at 0.65 GHz with a stop band depth of at least 50 dB and a weaker second-order gap at 1.3 GHz. The sample was also characterized using both its photonic and phononic stop band properties, i.e., consistently using Eqs. 1 and 2, which demonstrates the phoxonic nature (Sadat-Saleh et al. 2009) of porous silicon superlattices. 

Parsons and Andrews (2012), building on their earlier work (Parsons and Andrews 2009), have presented a comprehensive analysis of the complex phononic structure observable in porous silicon superlattices. This fully integrates the modeling of the photonic and phonic nature of the ADBRs... 

Moctezuma-Enriquez D, Rodriguez-Viveros YJ, Manzanares-Martinez MB, Castro-Garay P, Urrutia-Banuelos E, Manzanares-Martinez J (2011) Existence of a giant hypersonic elastic mirror in porous silicon superlattices. Appl Phys Lett 99 171901 Newell WE (1965) Face-mounted piezoeleetrie resonators. Proc IEEE 53 361-366 Parsons LC, Andrews GT (2009) Observation of hypersonic phononic crystal effects in porous silicon superlattices. Appl Phys Lett 95 241909... 

Lin, X.M., Jaeger, H.M., Sorensen, C.M. and Klabunde, K.J. (2001) Formation of long-range-ordered nanocrystal superlattices on silicon nitride substrates. Journal of Physical Chemistry B, 105 (17), 3353-3357. 

Jiang, C.-W. Green, M. A. 2006. Silicon quantum dot superlattices Modeling of energy bands, densities of states, and mobilities for silicon tandem solar cell applications. J. Appl. Phys. 99 114902-114909. 

T. G. Brown and D. G. Hall, Radiative Isoelectronic Impurities in Silicon and Silicon-Germanium Alloys and Superlattices J. Michel, L. V. C. Assail, M. T. Morse, and L. C. Kimerling, Erbium in Silicon K Kanemitsu, Silicon and Germanium Nanoparticles... 

Monolayers of alkyl chains on silicon are a significant addition to the family of SAMs. An ability to directly connect organic materials to silicon allows a direct coupling between organic materials and semiconductors. The fine control of superlattice structures provided by the self-assembly technique offers a route for building organic thin films with, for example, electrooptic properties on silicon. 

Keywords Silicon, germanium, carbon, alloys, nanostructures, optoelectronics, light emission, photoluminescence, electroluminescence, quantum well, quantum wire, quantum dot, superlattices, quantum confinement. 

T. G. Brown and D. G. Hall, Radiative Isoelectronic Impurities in Silicon and Silicon-Germanium Alloys and Superlattices... 

Crystalline and amorphous silicons, which are currently investigated in the field of solid-state physics, are still considered as unrelated to polysilanes and related macromolecules, which are studied in the field of organosilicon chemistry. A new idea proposed in this chapter is that these materials are related and can be understood in terms of the dimensional hierarchy of silicon-backbone materials. The electronic structures of one-dimensional polymers (polysilanes) are discussed. The effects of side groups and conformations were calculated theoretically and are discussed in the light of such experimental data as UV absorption, photoluminescence, and UV photospectroscopy (UPS) measurements. Finally, future directions in the development of silicon-based polymers are indicated on the basis of some novel efforts to extend silicon-based polymers to high-dimensional polymers, one-dimensional superlattices, and metallic polymers with alternating double bonds. 

CL(oo,oo n) is realized by superlattice structures such as Si and Ge multiquantum wells, in which n values correspond to the silicon layer thickness. 

Band gap dependence on network dimensions and unit numbers is summarized in Figure 5. Curve u shows the variation irom disilane to polysilane. For curve v, n = 1 corresponds to polysilane, and n = 2 corresponds to a ladder polymer the limiting case is siloxene. Curve w shows the energy gap changes for superlattices of different layer thickness, and it approaches the curve for crystalline silicon. 

An example of a one-dimensional superlattice structure is structure 1, which is an ordered copolymer. The skeleton is formed by silicon and germanium atoms. A unit cell is three times larger than that of a homopolymer. The band structure of this ordered copolymer changes to the zone-folded profile, which may result in a characteristic absorption spectrum. 

Future studies should concentrate on four types of silicon-based polymers semiconducting polymers, functional polymers, metallic polymers, and ideal low-dimensional materials for pure physics. The range of Si-based polymers should be expanded rapidly to include high-dimensional polymers, one-dimensional superlattices, and unsaturated polymers. 

Molecular dynamics simulations entail integrating Newton s second law of motion for an ensemble of atoms in order to derive the thermodynamic and transport properties of the ensemble. The two most common approaches to predict thermal conductivities by means of molecular dynamics include the direct and the Green-Kubo methods. The direct method is a non-equilibrium molecular dynamics approach that simulates the experimental setup by imposing a temperature gradient across the simulation cell. The Green-Kubo method is an equilibrium molecular dynamics approach, in which the thermal conductivity is obtained from the heat current fluctuations by means of the fluctuation-dissipation theorem. Comparisons of both methods show that results obtained by either method are consistent with each other [55]. Studies have shown that molecular dynamics can predict the thermal conductivity of crystalline materials [24, 55-60], superlattices [10-12], silicon nanowires [7] and amorphous materials [61, 62]. Recently, non-equilibrium molecular dynamics was used to study the thermal conductivity of argon thin films, using a pair-wise Lennard-Jones interatomic potential [56]. 

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