FTIR studies of H2O and D2O decomposition on porous silicon surfaces

Gupta, Pawan; Dillon, Anne C.; Bracker, A. S.; George, Steven M.

doi:10.1016/0039-6028(91)90038-t

Cited by 196 publications

(138 citation statements)

References 50 publications

Supporting

Mentioning

133

Contrasting

Order By: Relevance

“…These higher energy Si ± H x vibrations are characteristic of Si ± H species that have oxygen atoms bound to the Si atom. [17] Figure 4 also shows that the loss in intensity of the n (Si±Hx) band is offset by increased intensity in the n (OSi±Hx) band. Traces of surface-adsorbed DNT are also detected in the FTIR spectrum as absorptions at 1550 and 1340 cm À1 , which resemble those in the FTIR spectrum in a KBr pellet sample of DNT.…”

mentioning

confidence: 83%

Detection of Nitrobenzene, DNT, and TNT Vapors by Quenching of Porous Silicon Photoluminescence

2000

View full text Add to dashboard Cite

The detection of nitroaromatic molecules in air by the quenching of the photoluminescence of porous silicon (porous Si) films has been explored. Detection is achieved by monitoring the photoluminescence (PL) of a nanocrystalline porous Si film on exposure to the analyte of interest in a flowing air stream. The photoluminescence is quenched on exposure to the nitroaromatic, presumably by an electron-transfer mechanism. Detection limits of 500 parts-per-billion (ppb), 2 ppb, and 1 ppb were observed for nitrobenzene, 2.4-dinitrotoluene (DNT), and 2,4,6-trinitrotoluene (TNT), respectively (exposure times of 5 min for each, in air). Specificity for detection is achieved by catalytic oxidation of the nitroaromatic compound. A platinum oxide (PtO2) or palladium oxide (PdO) catalyst at 250 degrees C. placed in the carrier gas line upstream of the porous Si detector, causes oxidation of all the nitroaromatic compounds studied. The catalyst does not oxidize benzene vapor, and control experiments show no difference in the extent of PL quenching by benzene with or without an upstream catalyst. The PL quenching by NO2, released in the catalytic oxidation of nitroaromatic compounds, is less efficient than the quenching of the intact nitroaromatic compound. This provides a means to discriminate nitro-containing molecules from other organic species.

show abstract

mentioning

confidence: 83%

Detection of Nitrobenzene, DNT, and TNT Vapors by Quenching of Porous Silicon Photoluminescence

2000

View full text Add to dashboard Cite

show abstract

“…A d Si-H 2 scissor mode absorption is present at 908 cm ±1 , and features associated with Si lattice modes appear at 627 and 667 cm ±1 . [8,9] Upon exposure of the sample to the anionic surfactant SDSulfonate, new bands appear in the FTIR spectrum at 2930, 2847, 1469, and 1184 cm ±1 (Fig. 1B).…”

Section: Porous Si Samples Exposed To the Anionic Surfactant Sodium Dmentioning

confidence: 99%

“…5) show that extensive oxidation of the surface occurs upon treatment with aqueous DTAB. After exposure, a strong band at 1072 cm ±1 assigned to a m Si-O vibrational mode is observed, [8,9] along with bands assigned to aliphatic m C-H stretching modes of the surfactant at 2923 and 2858 cm ±1 (Fig. 5B).…”

Section: Porous Si Samples Exposed To the Cationic Surfactant Dodecylmentioning

confidence: 99%

“…In addition, a decrease is observed in the intensity of the bands assigned to m Si-H stretching vibrations in the 2080±2140 cm ±1 region, and a new m Si-H stretching mode appears at 2250 cm ±1 , which has been assigned to the hydride of silicon bonded to oxygen atoms (m OSi-H ). [9] The oxide cannot be removed with an ethanol rinse. The data show that a significant amount of oxidation occurs upon exposure to the cationic surfactant.…”

Section: Porous Si Samples Exposed To the Cationic Surfactant Dodecylmentioning

confidence: 99%

See 1 more Smart Citation

The Effect of Surfactants on the Reactivity and Photophysics of Luminescent Nanocrystalline Porous Silicon

et al. 2002

View full text Add to dashboard Cite

The effect of aqueous cationic and anionic surfactant solutions on the chemical stability and photoluminescence (PL) of n‐ and p‐type porous Si has been studied. Exposure of either n‐ or p‐type porous Si to aqueous solutions of the surfactants dodecyltrimethyl ammonium bromide (DTAB) or sodium dodecylsulfonate (SDSulfonate) at ≤ pH 3.0 results in quenching of the visible PL from this material via two distinct mechanisms. In the case of the cationic surfactant DTAB, irreversible quenching of the PL is accompanied by chemical corrosion of the porous Si sample, as determined by infrared spectroscopy. The enhanced corrosion rate is attributed to an increase in the reactivity of the hydrides present on the Si surface towards water, induced by adsorption of the cationic surfactant. Hydrogen evolution in this reaction was confirmed by gas chromatography. In contrast, the anionic surfactant SDSulfonate physisorbs to either n‐ or p‐type porous Si samples, and quenches PL without resulting in a significant amount of oxidation. The mechanism of quenching for the anionic surfactant is attributed to local dielectric effects that increase the non‐radiative decay rate in porous Si.

show abstract

“…Porous silicon (PS) is a semiconductor in nanocrystalline form (NPS), which could improve some properties of silicon, given that some properties, such as the electricals, are determined by the short range order of atoms, rather than by the long range order. In recent years, the great interest in NPS has been due to the high surface area of porous silicon, which has been useful as a model of crystalline silicon surfaces in spectroscopic studies (Anderson et al, 1990;Bisi et al, 2000;Dillon et al, 1992;Gupta et al, 1991), as a precursor to generate thick oxide layers on silicon and as a dielectric layer in capacitance chemical sensors. In addition, NPS has been applied in optoelectronics, micro-optics, energy conversion, environmental monitoring, wafer technology, micromachining and biotechnology.…”

Section: Introductionmentioning

confidence: 99%

Nanocrystalline Porous Silicon: Structural, Optical, Electrical and Photovoltaic Properties

Arenas‐Arrocena¹,

Vega-González²,

Martínez³

et al. 2011

Crystalline Silicon - Properties and Uses

View full text Add to dashboard Cite

FTIR studies of H2O and D2O decomposition on porous silicon surfaces

Cited by 196 publications

References 50 publications

Detection of Nitrobenzene, DNT, and TNT Vapors by Quenching of Porous Silicon Photoluminescence

Detection of Nitrobenzene, DNT, and TNT Vapors by Quenching of Porous Silicon Photoluminescence

The Effect of Surfactants on the Reactivity and Photophysics of Luminescent Nanocrystalline Porous Silicon

Nanocrystalline Porous Silicon: Structural, Optical, Electrical and Photovoltaic Properties

Contact Info

Product

Resources

About