EFFECT OF CHLORINATION ON PHOTOLUMINESCENCE PROPERTIES OF POROUS SILICON

2007 ◽  
Vol 06 (01) ◽  
pp. 17-22
Author(s):  
B. NATARAJAN ◽  
V. RAMAKRISHNAN ◽  
V. VASU ◽  
S. RAMAMURTHY
Keyword(s):  
Porous Silicon ◽  
Analytical Solution ◽  
Significant Role ◽  
Simulation Study ◽  
Surface Passivation ◽  
Photoluminescence Properties ◽  
Emission Efficiency ◽  
Capacitance Method ◽  
P Type ◽  
Effect Of Surface

The surface passivation of porous silicon plays a significant role in emission efficiency of the material. Photoluminescence (PL) studies were carried out for p-type porous silicon and chlorinated porous silicon to understand the effect of surface passivation on porous silicon. Visible photoluminescence was observed at 625 nm for both porous silicon and chlorinated porous silicon. The whole sample exhibits a PL band at red region and intensity decreased in chlorinated porous silicon. This paper presents an analytical solution that covers contributions from the components of silicon tetra chloride interface, silicon backbone, and voids using a serial–parallel capacitance method. Simulation study indicates that there is a good correlation between theory and observed PL.

STRUCTURAL AND PHOTOLUMINESCENCE PROPERTIES OF POROUS SILICON: EFFECT OF SURFACE PASSIVATION

2005 ◽  
Vol 12 (04) ◽  
pp. 645-649 ◽  
Author(s):  
B. NATARAJAN ◽  
V. RAMAKRISHNAN ◽  
V. VASU ◽  
S. RAMAMURTHY
Keyword(s):  
Porous Silicon ◽  
Surface Coverage ◽  
Surface Passivation ◽  
Material Surface ◽  
Photoluminescence Properties ◽  
Hydrogen Atoms ◽  
Emission Efficiency ◽  
Determining Factor ◽  
Effect Of Surface

The surface passivation of porous silicon is a determining factor in the emission efficiency of the material. The hydrogen surface coverage has been shown to provide very efficient passivation. In this work, we have monitored Si–H n surface coverage, which is readily-obtained porous silicon formed at 1:3 concentrations of HF: ethanol with/without HCl content in the electrolytes, and relate it to the emission efficiency. SEM, FTIR and PL studies were carried out to understand the role of HCl content in the electrolytes. When samples are anodized with HCl content in the electrolytes, there is a net decrease in the concentration of the Si–H groups on the material surface. This treatment provokes desorption of the hydrogen atoms and results in a drastic decrease in the photoluminescence.

Electroluminescence and Photoluminescence Properties of Porous Silicon Nanostructures with Optimum Current Density of Photo-Electrochemical Anodisation

2013 ◽  
Vol 667 ◽  
pp. 180-185
Author(s):  
M. Ain Zubaidah ◽  
F.S. Husairi ◽  
S.F.M. Yusop ◽  
Noor Asli Asnida ◽  
Mohamad Rusop ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Volume Ratio ◽  
Boron Doping ◽  
Peak Position ◽  
Silicon Nanostructures ◽  
Etching Time ◽  
Photoluminescence Properties ◽  
Current Densities ◽  
Pl Spectrum ◽  
P Type

P-type silicon wafer ( orientation; boron doping; 0.75 ~ 10 Ω cm-1) was used to prepare samples of porous silicon nanostructures (PSiNs). All samples have been prepared by using photo-electrochemical anodisation. A fixed etching time of 30 minutes and volume ratio of electrolyte, hydrofluoric acid 48% (HF48%) and absolute ethanol (C2H5OH), 1:1 were used for various current densities, J. There were sample A (J=10 mA/cm2), sample B (J=20 mA/cm2), sample C (J=30 mA/cm2), sample D (J=40 mA/cm2) and sample E (J=50 mA/cm2). Photoluminescence (PL) and electroluminescence (EL) spectra were investigated. Maximum peak position of PL spectrum at about ~675 nm, while the maximum EL spectrum at about ~650 nm (which is similar to the PL spectrum).

Lifetime Measurements of Stain Etched and Passivated Porous Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
Ricardo Guerrero-Lemus ◽  
Fathi A. Ben-Hander ◽  
Cristoffer Ballif ◽  
Ali Kenanoglu ◽  
Dietmar Borchert ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Vapour Deposition ◽  
Surface Passivation ◽  
Chemical Vapour ◽  
Lifetime Measurements ◽  
Porous Layers ◽  
Si Substrates ◽  
Before And After ◽  
P Type ◽  
Weak Influence

AbstractIn this work we present the first experimental study of photocarrier lifetimes in p-type and n-type Si substrates in which stain etched porous silicon (PS) has been formed on the surface. The lifetime values have been obtained before and after the surface passivation of the samples. The surface pasivation has been produced by two different techniques: (i) hydrogen passivation by immersion of the samples in a HF solution; and (ii) deposition of SiNx in a plasma enhanced chemical vapour deposition system. The results show a degradation of the photocarrier lifetime when the porous layers are not adequately passivated. This lifetime degradation is mainly associated to a large concentration of rapid recombination centres located at the Si/PS interface. We have also detected a weak influence of the PS outermost dangling bonds to the photocarrier lifetimes.

Modification of Visible Light Emission from Silicon Nanocrystals as a Function of Size, Electronic Structure, and Surface Passivation

1998 ◽  
Vol 536 ◽  
Author(s):  
M.V. Wolkin ◽  
J. Jorne ◽  
P.M. Fauchet ◽  
G. Allan ◽  
C. Delerue
Keyword(s):  
Porous Silicon ◽  
Silicon Nanocrystals ◽  
Surface Passivation ◽  
Light Emission ◽  
Electrochemical Etching ◽  
Theoretical Calculations ◽  
Surface Oxidation ◽  
Stain Etching ◽  
Visible Light Emission ◽  
Effect Of Surface

AbstractThe effect of surface passivation and crystallite size on the photoluminescence of porous silicon is reported. Oxygen-free porous silicon samples with medium to ultra high porosities have been prepared by using electrochemical etching followed by photoassisted stain etching. As long as the samples were hydrogen-passivated the PL could be tuned from the red (750nm) to the blue (400nm) by increasing the porosity. We show that when surface oxidation occurred, the photoluminescence was red-shifted. For sizes smaller than 2.8nm, the red shift can be as large as 1eV but for larger sizes no shift has been observed. Comparing the experimental results with theoretical calculations, we suggest that the decrease in PL energy upon exposure to oxygen is related to recombination involving an electron or an exciton trapped in Si=O double bonds. This result clarifies the recombination mechanisms in porous silicon.

Study of the Behavior of Positronium Annihilation in Porous Silicon

2012 ◽  
Vol 733 ◽  
pp. 203-206 ◽  
Author(s):  
Bao Yi Wang ◽  
Run Sheng Yu ◽  
Xing Zhong Cao ◽  
Zhuo Xin Li ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Porous Structure ◽  
Thermal Oxidation ◽  
Photoluminescence Properties ◽  
Positron Annihilation Lifetime ◽  
Positronium Annihilation ◽  
P Type ◽  
The Relationship ◽  
Interconnected Pores ◽  
Type Sample

The annihilation behavior of positronium in N and P type porous silicon is investigated via positron annihilation lifetime (PAL) and positronium time-of-flight (Ps-TOF) measurements. The result shows the N type sample has smaller positronium annihilation fraction and more interconnected pores. The microstructure of Rapid Thermal Oxidation (RTO) treated N type porous silicon also studied using PAL spectroscopy, and the relationship between its photoluminescence properties and porous structure was discussed.

Photoluminescence Properties of Porous Silicon Nanostructures (PSiNs) with Optimum Electrolyte Volume Ratio of Photo-Electrochemical Anodization

2012 ◽  
Vol 620 ◽  
pp. 40-44 ◽  
Author(s):  
Maslihan Ain Zubaidah ◽  
N.A. Asli ◽  
S.F.M. Yusop ◽  
Mohamad Rusop ◽  
Saifollah Abdullah
Keyword(s):  
Porous Silicon ◽  
Light Emitting Diode ◽  
Volume Ratio ◽  
Electrochemical Anodization ◽  
Silicon Nanostructures ◽  
Etching Time ◽  
Photoluminescence Properties ◽  
Light Emitting ◽  
Flat Screen ◽  
P Type

Porous silicon nanostructures light-emitting diode (PSiNs-LED) will be a device for future flat screen display and can be high in demand. Main purpose of this experiment is to determine the photoluminescence properties of porous silicon nanostructures (PSiNs). PSiNs samples were prepared using photo-electrochemical anodization. P-type silicon substrate was used for this experiment. For the formation of PSiNs, a fixed current density (J=20 mA/cm2) and 30 minutes etching time was applied for the variety of electrolyte volume ratio. Volume ratio of hydrofluoric acid 48% (HF48%) and absolute ethanol (C2H5OH), HF48%:C2H5OH, were used for samples 3:1, 2:1, 1:1, 1:2 and 3:1. The effective photoluminescence properties was observed for sample C.

Distinguishing the effect of surface passivation from the effect of size on the photonic and electronic behavior of porous silicon

2004 ◽  
Vol 96 (3) ◽  
pp. 1704-1708 ◽  
Author(s):  
L. K. Pan ◽  
Chang Q. Sun ◽  
G. Q. Yu ◽  
Q. Y. Zhang ◽  
Y. Q. Fu ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Surface Passivation ◽  
Electronic Behavior ◽  
Effect Of Surface

scholarly journals Влияние малых доз гамма-излучения на оптические свойства пористого кремния

2018 ◽  
Vol 52 (3) ◽  
pp. 349
Author(s):  
Д.И. Биленко ◽  
О.Я. Белобровая ◽  
Д.В. Терин ◽  
В.В. Галушка ◽  
И.В. Галушка ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Short Wavelength ◽  
Wavelength Region ◽  
Low Doses ◽  
Photoluminescence Properties ◽  
Short Wavelength Region ◽  
Emission Efficiency ◽  
Radioisotope Source

AbstractThe possibility of modifying the photoluminescence properties of porous silicon by irradiation with low doses of γ photons from a ^226Ra radioisotope source and bremsstrahlung is demonstrated. The position of the longest photoluminescence wavelength tends to shift to the short-wavelength region of the spectrum. The emission efficiency increases upon irradiation of both the substrate and the layer formed.

scholarly journals Analytical solution of one-dimensional Pennes’ bioheat equation

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 1084-1092
Author(s):  
Hongyun Wang ◽  
Wesley A. Burgei ◽  
Hong Zhou
Keyword(s):  
Analytical Solution ◽  
Radiofrequency Energy ◽  
Bioheat Equation ◽  
Surface Cooling ◽  
One Dimensional ◽  
The Fourier Transform ◽  
The One ◽  
Parameter Values ◽  
Mathematical Derivation ◽  
Effect Of Surface

Abstract Pennes’ bioheat equation is the most widely used thermal model for studying heat transfer in biological systems exposed to radiofrequency energy. In their article, “Effect of Surface Cooling and Blood Flow on the Microwave Heating of Tissue,” Foster et al. published an analytical solution to the one-dimensional (1-D) problem, obtained using the Fourier transform. However, their article did not offer any details of the derivation. In this work, we revisit the 1-D problem and provide a comprehensive mathematical derivation of an analytical solution. Our result corrects an error in Foster’s solution which might be a typo in their article. Unlike Foster et al., we integrate the partial differential equation directly. The expression of solution has several apparent singularities for certain parameter values where the physical problem is not expected to be singular. We show that all these singularities are removable, and we derive alternative non-singular formulas. Finally, we extend our analysis to write out an analytical solution of the 1-D bioheat equation for the case of multiple electromagnetic heating pulses.

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