Nanoparticles porous silicon

In 1990, Canham reported the room-temperature luminescence of porous silicon.11111 This important discovery has attracted much attention towards an investigation in silicon with the quantum-size effect. Through chemical-vapor deposition, it is also possible to load silicon nanoparticles into zeolite channels and pores. First, disilane is treated with the protons in a zeolite and is grafted to the zeolite walls [Equation (9.13)] ... 

Lie LH, Patole SN, Pike AR, Ryder LC, Connolly BA, Ward AD, Tuite EM, Houlton A, Horrocks BR (2004) Immobilisation and synthesis of DNA on Si(l 11), nanocrystalline porous silicon and silicon nanoparticles. Faraday Discuss 125 235-249... 

Another remarkable synthetic effort has been made by the preparation of colloidal Q-particles of the technically more relevant IV-IV materials (i.e., silicon and germanium) [20-25]. Silicon nanoparticles, especially, are currently drawing a lot of attention, since it was found by Canham [26] that nanostructured silicon formed under anodic etching of silicon wafers (called porous silicon ) exhibits bright red fluorescence. Due to the indirect nature of the band transition, bulk silicon shows, by contrast, almost no fluorescence and thus cannot be utilized for optoelectronic devices. 

Since the discovery of the intense red photoluminescence of porous silicon,much work has been devoted to this particular nanostructured material and, in the meantime, also to silicon nanoparticles. An important issue in current studies is the influence of the passivation on the photoluminescence properties. It has already been noted that, in the quantum... 

Impregnation of porous silicon in air is known [16] to come to slow oxidation of silicon nanoparticles in the pores. It becomes evident already after... 

Yakovlev and coworkers [402a, 402b] reported the IR absorption enhancement by mote than one order of magnitude for hydrocarbons adsorbed inside porous silicon, and assigned this effect to photon confinement in the microcavity acting like a multipass (Fabry-Perot type) cell. Recently, Jiang et al. [402c] observed a 50 times enhancement in the in situ IRRAS of CO adsorbed on Pd nanoparticles synthesized in cavities of Y-zeolite, as compared to the cases when the supports were ultrathin Pd films deposited directly on the zeolite or on amorphous alumosiUcate layer. 

Since the discovery of the intense red photoluminescence of porous silicon [1,2], much work has been devoted to this particular nanostructured material [4, 5] and, in the meantime, also to silicon nanoparticles [6, 7]. An important issue of current studies is the influence of the surface passivation on the photoluminescence properties. It has already been said that, in the quantum confinement model, it is essential that the surface is well passivated to avoid any dangling bonds [8]. Being middle-gap defects, these dangling bonds will quench the PL. On the other hand, the surface itself may lead to surface states that can be the origin of another kind of photoluminescence [9,10]. 

Noval AM, Vaquero VS, Quijoma EP, Costa VT, Perez DG, Mendez LG, Montero I, Palma RJM, Font AC, Ruiz JPG, Silvan MM (2012) Aging of porous silieon in physiologieal conditions cell adhesion modes on scaled Id micropattems. J Biomed Mater Res A 100A(6) 1615-1622 Park JH, Gu L, von Maltzahn G, Ruoslahti E, Bhatia SN, Sailor MJ (2009) Biodegradable luminescent porous silicon nanoparticles for in vivo applications. Nat Mater 8(4) 331-336 Pavesi L, Dubos P (1997) Random porous silicon multilayers application to distributed Bragg reflectors and interferential fabry - perot filters. Semicond Sci Technol 12(5) 570... 

Sarparanta MP, Bimbo LM, Makila EM, Salonen JJ, Laaksonen PH, Helariutta AMK, Linder MB, Hirvonen JT, Laaksonen TJ, Santos HA, Airaksinen AJ (2012) The mucoadhesive and gastroretentive properties of hydrophobin-coated porous silicon nanoparticle oral drug delivery systems. Biomaterials 33(ll) 3353-3362... 

Gu L, Ruff LE, Qin Z, Corr M, Hedrick SM, Sailor MJ (2012) Multivalent porous silicon nanoparticles enhance the immune activation potency of agonistic CD40 antibody. Adv Mater, doi 10.1002/adma.201200776... 

Henstock JR, Ruktanonchai UR, Canham LT, Anderson SI (2014) Porous silicon confers bioactivity to polycaprolactone composites in vitro. J Mater Sci 25(4) 1087-1097 Hon NK, Shaposhnik Z, Diebold ED, Tamanoi F, Jalali B (2012) Tailoring the biodegradability of porous silicon nanoparticles. J Biomed Mater Res 100(12) 3416-3421... 

Massive temperature rises in the silicon skeleton can occur, so much so that some degree of sintering or even localized melting occurs during analysis. This becomes more pronounced for porous silicon membranes and powders which are removed Ifom the bulk silicon heat sink and more pronounced when data is collected in vacuum, removing gaseous heat transport. Figure 4 provides an example where Raman analysis at gas pressures was used to demonstrate silicon nanoparticle temperatures up to 800 °C under focussed photoexcitation. 

A particularly striking example of this is the visible light emission from some porous silicon and silicon nanoparticle structures originally ascribed to photoluminescence but later revealed to be blackbody thermal radiation by careful experimentation (Costa et al. 1998 Roura and Costa 2002). Some very spectrally broad cathodoluminescence spectra published are also likely to be primarily thermal radiation, as discussed in the handbook chapter Cathodoluminescence of Porous Silicon. ... 

Ouyang H, Christopherson M, Fauchet PM (2005) Enhanced control of porous silicon morphology fi"om macropore to mesopore formation. Phys Stat Solidi (a) 202(8) 1396-1401 Pacholski C (2013) Photonic crystal sensors based on porous silicon. Sensors 13 4694-4713 Roura P, Costa J (2002) Radiative thermal emission from silicon nanoparticles a reversed story from quantum to classical theory. Eur J Phys 23 191-203 Scherer WG, Smith DM, Stein D (1995) Deformation of silica aerogels during characterisation. JNon Cryst Solids 186 309-315... 

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