Reversible and Irreversible Light-Induced Change of Photoluminescence in Porous Silicon

MRS Proceedings ◽

10.1557/proc-378-905 ◽

1995 ◽

Vol 378 ◽

Author(s):

Suk-Ho Choi ◽

Byoung-Hun Mun

Keyword(s):

Fourier Transform ◽

Porous Silicon ◽

Room Temperature ◽

Irreversible Process ◽

Laser Light ◽

Light Exposure ◽

Peak Position ◽

Continuous Laser ◽

Ftir Studies ◽

Pl Intensity

AbstractWe have investigated the light-induced change of photoluminescence(PL) and its recovery in porous silicon. The exposure of the porous silicon to continuous laser light in vacuum results in the quenching of the PL intensity, which is almost fully recovered by simply keeping the samples in vacuum or in air at room temperature for a few days. When the light exposure is done in air, the PL spectra of the samples with initial PL peak at 800 nm are blue-shifted to the peak position at 740 nm and the samples with the initial PL spectrum peaked at 740 nm shows only a rise of PL intensity without any change of its peak position. Fourier transform infrared(FTIR) studies suggest that the light-induced change of PL in air is a irreversible process and occurs as a result of optically induced replacement of some of the Si-H bonds with O-Si-H bonds or adsorption of oxygen with hydrogen loss.

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Degradation in a Methyl-phenyl Co-Polymeric Polysilane for LED Applications

MRS Proceedings ◽

10.1557/proc-769-h4.3 ◽

2003 ◽

Vol 769 ◽

Cited By ~ 2

Author(s):

Asha Sharma ◽

Deepak ◽

Monica Katiyar ◽

Satyendra Kumar ◽

V. Chandrasekhar ◽

...

Keyword(s):

Thin Films ◽

Molecular Weight ◽

Light Source ◽

Room Temperature ◽

Light Exposure ◽

Room Temperature Photoluminescence ◽

Pl Spectrum ◽

Pl Intensity ◽

Methyl Phenyl

AbstractThe optical degradation of polysilane copolymer has been studied in spin cast thin films and solutions using light source of 325 nm wavelength. The room temperature photoluminescence (PL) spectrum of these films show a sharp emission at 368 nm when excited with a source of 325 nm. However, the PL intensity deteriorates with time upon light exposure. Further the causes of this degradation have been examined by characterizing the material for its transmission behaviour and changes occurring in molecular weight as analysed by GPC data.

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Light Controlled Photoluminescence Relaxation in Porous Silicon

MRS Proceedings ◽

10.1557/proc-358-495 ◽

1994 ◽

Vol 358 ◽

Author(s):

R. Czaputa ◽

R. Fritzl ◽

A. Popitsch

Keyword(s):

Porous Silicon ◽

Chemical Structure ◽

Room Temperature ◽

Relaxation Effect ◽

Ambient Atmosphere ◽

Surface Chemical ◽

Dangling Bond ◽

Nanoporous Silicon ◽

Pl Intensity ◽

Modification Of The Surface

ABSTRACTWe report results of photoluminescence (PL), FTIR and ESR investigations on nanoporous silicon (PS) where a reversible PL intensity relaxation effect in the chemically oxidised material is observed. To be activated the effect needs, however, additional preparation steps including light irradiation and ageing in ambient atmosphere. After illumination with visible light, the PL intensity is remarkably diminished. However it recovers in the dark within the time scale of minutes to hours under ambient atmosphere at room temperature. This cycle can be repeated several times. We show that the variation of the PL intensity is anticorrelated to an ESR signal attributed to silicon dangling bonds. From the IR spectrum, however, no significant change of the pore surface chemical structure can be observed during a cycle. Therefore we conclude that the variation of the PL intensity is rather controlled by a metastable change in the number of dangling bond centers than by modification of the surface chemistry in the porous silicon system.

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Structure and Optical Properties of Porous Silicon Formed on Silicon Substrates Treated with Compression Plasma Flow

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.245.49 ◽

2015 ◽

Vol 245 ◽

pp. 49-54

Author(s):

Mikhail Victorovich Bozhenko ◽

Evgeniy Anatolievich Chusovitin ◽

Nikolay Gennadievich Galkin ◽

Evgeny Vladislavovich Pustovalov ◽

Vladimir Vadimovich Tkachev ◽

...

Keyword(s):

Porous Silicon ◽

Plasma Flow ◽

Wavelength Region ◽

Peak Position ◽

Silicon Substrates ◽

Intensity Increase ◽

Long Wavelength ◽

Bond Density ◽

Compression Plasma Flow ◽

Pl Intensity

Porous silicon layers were formed on the silicon substrates treated with compression plasma flow. Pores density and lateral size on substrates treated with plasma is by 25% more than that on untreated substrates. The intensity of the PL of the PS layers, formed on the plasma treated substrates (PT PS), is twice more than that of the PS layers, formed on untreated substrates. Three month exposure of normal PS and PT PS layers to the air leads to the PL intensity increase by 3 and 5.7 times, respectively, as well as to the peak position shifting towards long wavelength region by 3.1 nm, in the case of PT PS layer. The PL intensity increase is attributable to the reduction of the dangling bond density as a result of passivation by oxygen.

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Influence of AgNO3 on Photoluminescence Properties of Porous Silicon

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.486.239 ◽

2012 ◽

Vol 486 ◽

pp. 239-242 ◽

Cited By ~ 1

Author(s):

Hong Yan Zhang ◽

Xiao Yi Lv ◽

Zhen Hong Jia

Keyword(s):

Silver Nanoparticles ◽

Porous Silicon ◽

Specific Surface ◽

Room Temperature ◽

Photoluminescence Properties ◽

Pl Intensity ◽

Made In

Porous silicon (PS) has the strong photoluminescence (PL) at room temperature and high specific surface. In this paper, we have fabricated the PS coated with silver nanoparticles as a substrate. The result shows that the substrate made in this way is stable for more than twenty days and the strong PL intensity of PS is around 584nm after immersed into solution of AgNO3. The formation of SiAg bond was demonstrated to be responsible for the improvement of PL properties.

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FTIR Studies of CH3OH on Porous Silicon

MRS Proceedings ◽

10.1557/proc-358-399 ◽

1994 ◽

Vol 358 ◽

Cited By ~ 3

Author(s):

John A. Glass ◽

Edward A. Wovchko ◽

John T. Yates

Keyword(s):

Fourier Transform ◽

Infrared Spectroscopy ◽

Porous Silicon ◽

Fourier Transform Infrared Spectroscopy ◽

Porous Layer ◽

Fourier Transform Infrared ◽

Surface Species ◽

Carbon Incorporation ◽

Oxygen Incorporation ◽

Ftir Studies

ABSTRACTFourier transform infrared spectroscopy (FTIR) was used to investigate the reaction of methanol with porous silicon and hydrogen passivated porous silicon. At 300 K methanol adsorbs onto hydrogen free porous silicon by cleavage of the O-H bond. Both of the resulting surface species, Si-H and Si-OCH3, were determined to be stable up to ∼500 K. Above 500 K the Si-OCH3 moiety decomposes by breakage of the C-O and C-H bonds. The resulting carbon and oxygen were incorporated into the porous layer and additional Si-H surface species were detected. Further heating to 900 K removed the Si-H surface species. Adsorption of methanol onto hydrogen-passivated porous silicon did not occur until 600 K. At temperatures beyond 600 K, oxygen and carbon incorporation into the porous layer and Si-OCH3, Si-CH3, and Si-H surface species were seen. The previously unseen Si-CH3 surface species is believed to be stabilized by oxygen incorporation.

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The Role of Silicon Monohydride and Dihydride in the Photoluminescence of Porous Silicon and Photoluminescence of Porous Silicon Buried Underneath Epitaxial GaP

MRS Proceedings ◽

10.1557/proc-256-203 ◽

1991 ◽

Vol 256 ◽

Cited By ~ 4

Author(s):

C. Tsai ◽

K.-H. Li ◽

J. Sarathy ◽

K. Jung ◽

S. Shih ◽

...

Keyword(s):

Fourier Transform ◽

Porous Silicon ◽

Fourier Transform Infrared ◽

Wide Bandgap ◽

Photoluminescence Intensity ◽

Porous Si ◽

Sufficient Energy ◽

Pl Intensity ◽

Viable Method

ABSTRACTThermal annealing studies of the photoluminescence (PL) intensity and Fourier-transform infrared (FTIR) spectroscopy have been performed concurrently on porous Si. A sharp reduction in the PL intensity is observed for annealing temperatures > 300 °C and this coincides with desorption of hydrogen from the SiH2 surface species. The role of silicon hydride species on the photoluminescence intensity has been studied. The surfaces of luminescent porous Si samples were converted to a predominate SiH termination using a remote H-plasma. The as-passivated samples were then immersed in various concentrations of hydrofluouric solutions to regulate the recovery of SiH2 termination on the surface. Photoluminescence measurements and transmission Fourier-transform infrared spectroscopy have shown that predominant silicon monohydride (SiH) termination results in weak photoluminescence. In contrast, it has been observed that the appearance of silicon dihydride (SiH2) coincides with an increase in the photoluminescence intensity. To achieve electroluminescence it will be beneficial to generate carriers with sufficient energy to populate the states of the quantum-confined Si structures. A viable method to accomplish this is to utilize a wide-bandgap heterojunction injector such as GaP. Toward that end we report the successful formation of porous Si buried underneath GaP islands and we demonstrate that the buried porous Si layer exhibits strong photoluminescence.

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Effect of Surface Coverage on Porous Silicon Photoluminescence: Transmission FTIR Studies

MRS Proceedings ◽

10.1557/proc-256-17 ◽

1991 ◽

Vol 256 ◽

Cited By ~ 6

Author(s):

M. B. Robinson ◽

A. C. Dillon ◽

D. R. Haynes ◽

S. M. George

Keyword(s):

Fourier Transform ◽

Porous Silicon ◽

Ftir Spectroscopy ◽

Surface Coverage ◽

Ultrahigh Vacuum ◽

Photoluminescence Intensity ◽

Ftir Studies ◽

Photoluminescence Studies ◽

Effect Of Surface

ABSTRACTTransmission Fourier Transform Infrared (FTIR) Spectroscopy was utilized to monitor the effect of surface coverage on photoluminescent porous silicon. These experiments were performed in situ in an ultrahigh vacuum (UHV) chamber to correlate simultaneously surface coverage and photoluminescence intensity. The goal of these FTIR and photoluminescence studies was to clarify the mechanism of the photoluminescence from porous silicon.

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Scattering Rings in Birefringent Porous Silicon

MRS Proceedings ◽

10.1557/proc-762-a17.17 ◽

2003 ◽

Vol 762 ◽

Author(s):

Claudio J. Oton ◽

Zeno Gaburro ◽

Mher Ghulinyan ◽

Nicola Daldosso ◽

Lucio Pancheri ◽

...

Keyword(s):

Dielectric Constant ◽

Light Scattering ◽

Porous Silicon ◽

Direct Measurement ◽

Optical Anisotropy ◽

Oblique Incidence ◽

Laser Light ◽

Anisotropic Scattering ◽

Scattering Measurements

AbstractWe report the observation of strongly anisotropic scattering of laser light at oblique incidence on (100)-oriented porous silicon layers. We performed angle-resolved light scattering measurements and three concentric rings were observed. Modeling porous silicon by means of nanometric columnar air pores and an effective anisotropic uniaxial dielectric constant explains the observed phenomenon, and besides, the observation of the angle aperture of these rings allows a direct measurement of relative birefringence. We finally study the changes of optical anisotropy after different modifications of the structure.

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