Photoluminescence oxidized porous silicon

NHE OCP ONO OPS PCD PDS PL PLE PMMA PP PP PS PSG PSL PTFE PVC PVDF normal hydrogen electrode (= SHE) open circuit potential oxide-nitride-oxide dielectric oxidized porous silicon photoconductive decay photothermal displacement spectroscopy photoluminescence photoluminescence excitation spectroscopy polymethyl methacrylate passivation potential polypropylene porous silicon phosphosilicate glass porous silicon layer polytetrafluoroethylene polyvinyl chloride polyvinylidene fluoride... 

PHOTOLUMINESCENCE EXCITATION SPECTROSCOPY OF ERBIUM INCORPORATED WITH IRON IN OXIDIZED POROUS SILICON... 

Photoluminescence excitation (PLE) spectroscopy was carried out at 77K on oxidized porous silicon containing iron/erbium oxide clusters. The novel PLE spectrum of the 1535 nm Er PL band comprises a broad band extending from 350 to 570 nm and very week bands located at 640, 840, and 895 nm. The excitation at wavelengths of 400 - 560 nm was shown to be the most effective. No resonant PLE peaks related to the direct optical excitation of Er by absorption of pump photons were observed. The lack of the direct optical excitation indicates conclusively that Er is in the bound state and may be excited by the energy transfer within the clusters. 

Optical properties of dielectrics can be modified by incorporating nanosize clusters of foreign materials. Recently Si nanoclusters were shown to excite rare-earth element Er in the silica glass host [1,2]. The favorable effect of Si nanoclusters on the photoluminescence of Er in oxidized porous silicon (OPS) was also demonstrated [3], In silica hosts doped with Si nanoclusters it was shown that the excitation energy can be transferred from nanoclusters to Er ions located in a silicalike environment near the clusters. Nowadays, there is a principal interest to incorporate Er ions inside clusters due to influence on the excitation process. 

The as-prepared PS layers were firstly investigated with these complementary methods in order to achieve a complete image of the large internal area chemical map where about 20 % of the silicon atoms are located, looking forward to accomplish a general model for porosification process and also a mechanism for the most renowned property of this material, photoluminescence (see chapter Photoluminescence of Porous Silicon ). Table 2 provides example of the compositional studies of freshly prepared and passivated/oxidized PS. 

Bondarenko V, Kazuchits N, Volchek S (2003) Fine structure of photoluminescence spectra Irom erbium incorporated with iron in oxidized porous silicon. Phys Status Sohdi (A) 197 441—445 Boukherroub R, Wayner DDM, Lockwood DJ, Canham LT (2001) Passivated luminescent porous silicon. J Electrochem Soc 148 H91-H97... 

Takeda E, Nakamura T, Fujii M, Miura S, Hayashi S (2006) Surface plasmon polariton mediated photoluminescence from excitons in silicon nanocrystals. Appl Phys Lett 89(10) 101907 Tsybeskov L, Duttagupta SP, Fauchet PM (1995) Photoluminescence and electroluminescence in partially oxidized porous silicon. Solid State Commun 95(7) 429-433 Tsybeskov L, Duttagupta SP, Hirschman KD, Fauchet PM (1996) Stable and efficient electroluminescence from a porous silicon-based bipolar device. Appl Phys Lett 68(15) 2058-2060 Valenta J, Lalic N, Linnros J (2004) Electroluminescence of single silicon nanocrystals. Appl Phys Lett 84(9) 1459-1461... 

Bsiesy A, Vial JC, Gaspard F et al (1991) Photoluminescence of high porosity and of electrochem-ically oxidized porous silicon layers. Surf Sci 254 195-200 Canham L (ed) (1997) Properties of porous silicon. INSPEC - The Institution of Electrical... 

Much of the focus of this review will concentrate on HF + oxidants-other-than-NOs solutions. One prime motivation for this is that some of these solutions produce por-Si in a much more reliable, reproducible, and controllable manner. In particular, Loni et al. (2011) have demonstrated that Fe can be used to create high-surface area por-Si from low-cost metallurgical grade Si. Similarly, Sato and co-workers have used HNO3 + acetic acid + HF solutions (with added methanol and ultrasonic agitation) to produce Si nanocrystals with variable visible photoluminescence (Sato et al. 2009a, b). This property is reviewed elsewhere in this handbook (chapter Photoluminescence of Porous Silicon ). 

An influence of a weak magnetic field on the evolution of porous silicon surface species during ageing in air and porous silicon photoluminescence is studied. Magnetic field retards the process of Si surface oxidation and stimulates a breakage of Si-H bonds at the porous silicon surface. It also affects bond energy in silicon complexes witti water molecules. 

H. Miauno, H. Koyama, and N. Koshida, Oxide-free blue photoluminescence from photochemically etched porous silicon, Appl. Phys. Lett. 69(25), 3779, 1996. 

Ongoing investigations into the chemistry of porous silicon surfaces seek to develop methods for the preparation of chemically functional interfaces that protect the underlying silicon nanocrystallites from degradation without changing or annihilating their intrinsic behavior. The native, hydride-terminated surface is only metastable under ambient conditions and oxidation of freshly prepared porous silicon commences within minutes when exposed to air. While surface oxide can suitably passivate the nanocrystalline silicon and stabilize its photoluminescence, the electrically insulating and structurally defective character of this oxide layer... 

Platinum ions reduce to metallic Pt by injecting holes into the Si valence band. Thus Pt ions act as an oxidizing agent for silicon, and result in the simultaneous formation of photoluminescent porous silicon under certain conditions. Nickel ions may exchange charge with both the conduction and the valence band. The reduction of Ni ions competes with hydrogen evolution, and the deposition of Ni can only be achieved at high pH where it is kinetically faster. The role of silicon surface states as reaction intermediates is discussed. 

Thus, from the analysis of XANES and USXES data and SEM and AFM-images it follows that porous silicon is a multi-phase system containing nanocrystals of silicon covered with amorphous and oxide phases. Under laser excitation of visible photoluminescence electrons can transfer from conduction band bottom of the oxide phases to the valence band of silicon resulting in a broad luminescence band in the range of 1.8 - 2.4 eV. 

STRONG WHITE PHOTOLUMINESCENCE OF CARBON-RICH SILICON OXIDE FABRICATED BY WET OXIDATION OF CARBONIZED NANO CRYSTALLINE POROUS SILICON... 

Dian, X, Vrkoslav, V. and Jellnek, I. Recognition enhancement of oxidized and methyl-lO-undecenoate functionalized porous silicon in gas phase photoluminescence sensing , (2010) Sensor. Actual. B. 147,406-10. 

Song JH, Sailor MJ (1998a) Dimethyl sulfoxide as a mild oxidizing agent for porous silicon and its effect on photoluminescence. Inorg Chem 37 3355-3360... 

Zhang LZ, Zong BQ, Zhang BR, Xu ZH, Li JQ, Qin GG (1995) Photoluminescence peak energy evolution for porous silicon during photo-oxidation and y-ray oxidation. J Phys Condens Matter 7 697-704... 

Harper J, Sailor M (1996) Detection of nitric oxide and nitrogen dioxide with photoluminescent porous silicon. Anal Chem 68 3713... 

Petrova-Koch V, Muschik T, Kux A et al (1992) Rapid-thermal-oxidized porous Si-the superior photoluminescent Si. Appl Phys Lett 61 943-945 Porter LA, Choi HC, Ribbe AE et al (2002) Controlled electroless deposition of noble metal nanoparticle films on germanium surfaces. Nano Lett 2 1067-1071 Rabinal MK, Mulimani BG (2007) Transport properties of molecularly stabilized porous silicon schottky junctions. New J Phys 9 440-448... 

Gelloz B, Koshida N (2005) Mechanism of a remarkable enhancement in the light emission from nanocrystalline porous silicon annealed in high-pressure water vapor. J Appl Phys 98(1) 123509 Gelloz B, Koshida N (2006) Highly enhanced photoluminescence of as-anodized and electrochem-ically oxidized nanocrystalline p-type porous silicon treated by high-pressure water vapor annealing. Thin Solid Films 508(l-2) 406—409... 

Gelloz B, Koshida N (2007) Highly efficient and stable photoluminescence of nanociystalline porous silicon by combination of chemical modification and oxidation under high pressure. Jpn J Appl Phys Part 1 46(4B) 2429-2433... 

Wadayama T, Arigane T, Hayamizu K, Hatta A (2002) Unusual photoluminescence decay of porous silicon prepared by rapid thermal oxidation and quenching in liquid nitrogen. Mater Trans... 

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