Oxidized porous silicon as a non-interfering support for luminescent dyes

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
G. Santamaría-Juárez ◽  
E. Gómez-Barojas ◽  
E. Quiroga-González ◽  
E. Sánchez-Mora ◽  
J. A. Luna-López
Keyword(s):  
Experimental Study ◽  
Porous Silicon ◽  
Low Temperature ◽  
Thermal Oxidation ◽  
Surface States ◽  
Large Contribution ◽  
Porous Si ◽  
Host Matrix ◽  
Oxidized Porous Silicon ◽  
Pl Spectrum

AbstractThe objective of this work is to elucidate the possibility to passivate the surface states of porous Si (PSi) by thermal oxidation to be used as a passive host matrix. It is known that a large contribution to the Photoluminescence (PL) of PSi comes from defects at the surface. This PL could overlap the PL of guest materials making it difficult to identify the details of the PL spectrum of the guest. We report on an experimental study about the effect of thermal oxidation at low temperature on the PL of PSi and on the functionalization of oxidized PSi with fluorescein. The background PL is minimized allowing a better detection of fluorescein molecules adsorbed on oxidized PSi.

Gas Sensor Using an Aluminium-Porous Silicon Junction Application to the Detection of Non-Zero Molecular Dipole Moment

1994 ◽  
Vol 358 ◽  
Author(s):  
D. Stievenard ◽  
D. Deresmes
Keyword(s):  
Dipole Moment ◽  
Porous Silicon ◽  
Silicon Oxide ◽  
Surface States ◽  
Dangling Bonds ◽  
Porous Si ◽  
Adsorbed Gas ◽  
Dipole Layer ◽  
Dc Current ◽  
Partial Depletion

ABSTRACTPorous silicon is known to be sensitive to moisture. Using an aluminium-porous p+ silicon junction, we have realized a sensor which dc current increases up to two orders of magnitude in the presence of ammoniac. We have tested a series of various gases and we show that if the dipole moment of the molecule is zero, there is no effect on the dc current. To interpret quantitatively this phenomenon, we assume that the conductivity is governed by the width of a channel resulting from the partial depletion of silicon located between two pores. This depleted region is due to the charges trapped on surface states associated with the Si-SiO2 interface where SiO2 is the native silicon oxide. When some gas is adsorbed, we propose there is a passivation of the interface states (mainly dangling bonds), leading to a decrease of the depleted region, i.e. an increase of the width of the channel and thus an increase of the current. The adsorbed gas gives a dipole layer at the surface of the pore. This layer has no influence on the depleted region. It stabilizes electrons or holes at the porous Si surface, allowing a stable charge state of the dangling bonds.

Visible Photoluminescence From Rapid-Thermal-Oxidized Porous Silicon

1993 ◽  
Vol 298 ◽  
Author(s):  
Y. Kanemitsu ◽  
T. Matsumoto ◽  
T. Futagi ◽  
H. Mimura
Keyword(s):  
Electronic Structure ◽  
Porous Silicon ◽  
Electrochemical Etching ◽  
Electronic Structure Calculations ◽  
Porous Si ◽  
Silicon Oxides ◽  
Visible Photoluminescence ◽  
Oxidized Porous Silicon ◽  
Structure Calculations ◽  
Silicon Oxygen

AbstractWe have studied the origin of the visible photoluminescence (PL) from oxidized porous Si. The hydrogen–passivated surface of porous Si prepared by electrochemical etching is converted to stable silicon oxides by rapid–thermal–oxidization processes. At low oxidation temperature (Tox), the PL spectrum with a peak near 700 nm is observed. At high Tox above 800 °C, a strong blue PL is observed near 400 nm. We discuss the origin of blue and red PL by employing the results of ab initio electronic structure calculations of silicon–oxygen compounds.

The Visible and the Infrared Luminescence Bands as a Tool for Characterization of the Porous Silicon Bandstructure

1994 ◽  
Vol 358 ◽  
Author(s):  
V. Petrova-Koch ◽  
T. Muschik ◽  
G. Polisski ◽  
D. Kovalev
Keyword(s):  
Porous Silicon ◽  
Low Temperature ◽  
Valence Band ◽  
Conduction Band ◽  
Porous Si ◽  
Surface Degradation ◽  
Infrared Luminescence

ABSTRACTThe visible and the infrared photoluminescence bands in porous Si have been studied at low temperature for two series of samples: one in which the size of the crystallites has been varied and another in which the degree of surface degradation has been changed. It is shown that the relation of the two bands can be explored for characterization of the porous Si bandstructure. The size- and the surface dependence of the valence band and of the conduction band related states is discussed. A model is proposed for explanation.

scholarly journals Tuning the fluorescence intensity and stability of porous silicon nanowires via mild thermal oxidation

RSC Advances ◽  
2017 ◽  
Vol 7 (55) ◽  
pp. 34579-34583 ◽  
Author(s):  
Lu Gan ◽  
Haiping He ◽  
Qianqian Yu ◽  
Zhizhen Ye
Keyword(s):  
Porous Silicon ◽  
Thermal Oxidation ◽  
Fluorescence Intensity ◽  
Silicon Nanowires ◽  
Luminescence Quenching ◽  
Porous Si ◽  
Si Nanowires ◽  
Porous Silicon Nanowires

Porous Si nanowires show anomalous luminescence quenching and improved sensing stability upon mild thermal oxidation.

Identification of the luminescence center of porous silicon under low temperature thermal oxidation

2000 ◽  
Vol 638 ◽  
Author(s):  
Kazuo Goda ◽  
Ryuji Tanaka ◽  
Yukako Honda ◽  
Kazuhisa Inoue ◽  
Hideki Ohno
Keyword(s):  
Porous Silicon ◽  
Thermal Oxidation ◽  
Low Temperatures ◽  
Luminescence Center ◽  
Blue Shift ◽  
Oxidation Time ◽  
Ir Absorption ◽  
Initial Oxidation ◽  
Chemical States ◽  
Pl Spectrum

AbstractThe relationship between chemical states and optical properties for porous silicon (PS) under initial oxidation by heating at low temperatures (150, 200, 250 °C) in air was investigated using an infrared (IR) spectroscopy and photoluminescence (PL) measurements. The measurements in the IR region show that the IR absorption peaks for the Si-H stretching band (2050-2150 cm−1) change with appearance of the Si-O-Si-H stretching band (2100-2300 cm−1) when the thermal oxidation time is increased. On the other hand, the peak in the PL spectrum shows a blue shift from 820 nm to 710 nm with the oxidation time. The observed blue shift of the PL spectrum is due to the decrease in the initial PL peak intensity at 820 nm and the increase at 710 nm. Moreover, the peak intensities in the PL spectra at 820 nm and 710 nm have clear relationship to the amounts of the Si-H bonds and Si-O-Si-H bonds, respectively, as a function of the oxidation time.These results indicate that luminescence center (LC) for as-prepared PS is ascribed to complexes including Si-H bonds. Also the LC for oxidized PS under the oxidation process at low temperatures is ascribed to complexes including Si-O-Si-H bonds covering the inner surface of PS.

Buried Insulators and/or Conductors in Singles-Crystal Silicon Using Porous Silicon Techniques

1987 ◽  
Vol 107 ◽  
Author(s):  
Sylvia S. Tsao
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
Pore Network ◽  
Silicon On Insulator ◽  
Large Surface Area ◽  
Porous Si ◽  
Multilayered Structures ◽  
Crystal Silicon ◽  
Oxidized Porous Silicon ◽  
Interconnected Pore

AbstractPorous silicon lends itself to a variety of applications due to its unique characteristics such as an interconnected pore network, large surface area, and dopant-dependent selectivity of formation. Although the best-known application of porous Si is for silicon-on-insulator (SOI) fabrication, the porous silicon technique also offers elegant approaches for silicon-on-conductor (SOC) fabrication.In this paper, we present an overview of porous Si techniques for both SOI and SOC applications. Possible limitations of the oxidized porous silicon process, for SOI in particular, are discussed. We also consider novel and multilayered structures which might be obtained using porous silicon.

Intense Visible Luminescence from Thermally-Oxidized Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
S. Miyazakj ◽  
K. Shiba ◽  
K. Sakamoto ◽  
M. Hirose
Keyword(s):  
Porous Silicon ◽  
Light Emission ◽  
Excitation Power ◽  
Thermally Grown Oxide ◽  
Localized States ◽  
Porous Si ◽  
Time Resolved ◽  
Visible Luminescence ◽  
Oxidized Porous Silicon ◽  
The Ideal

ABSTRACTPhotoluminescence from porous silicon oxidized at 800 or 900°C in an N2 +O2 gas mixture has been investigated. The ideal passivation of the porous Si surface with thermally grown oxide results in stable, intense visible-light emission. The steady-state and time-resolved luminescence measured as functions of temperature and excitation power have indicated that a possible pathway for the light emission is the radiative recombination through localized states.

Origin of Blue Photoluminescence from Naturally Oxidized Porous Silicon

2011 ◽  
Vol 181-182 ◽  
pp. 374-377 ◽  
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Porous Silicon ◽  
Fluorescence Spectroscopy ◽  
Silicon Oxide ◽  
Silicon Films ◽  
The Other ◽  
Oxidized Porous Silicon ◽  
Pl Spectrum ◽  
Blue Photoluminescence

Upon the 325 nm excitation from a helium-cadmium laser, the photoluminescence (PL) from aged porous silicon was investigated with fluorescence spectroscopy. Each PL spectrum of the aged porous silicon films contained two luminescent bands, one of the luminescent bands peaked at about 466.7 nm whereas the other luminescent band peaked at about 596.1 nm. The origin of the blue PL from aged porous silicon was discussed, and our results indicated that the blue photoluminescence of porous silicon films originated from the silicon oxide itself.

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