Porous Silicon Photoluminescence Versus HF Etching: No Correlation with Surface Hydrogen Species

1992 ◽  
Vol 283 ◽  
Author(s):  
M. B. Robinson ◽  
A. C. Dillon ◽  
S. M. George
Keyword(s):  
Porous Silicon ◽  
Ftir Spectroscopy ◽  
Hydrofluoric Acid ◽  
Etching Time ◽  
Photoluminescence Intensity ◽  
Surface Species ◽  
Initial Sample ◽  
Surface Hydrogen

ABSTRACTThe photoluminescence and infrared absorbance of electrochemically anodized porous silicon samples were examined as a function of hydrofluoric acid (HF) etching time. Transmission FTIR spectroscopy measurements revealed that the infrared absorbance from silicon hydrogen surface species was largest for the initial porous silicon samples and immediately decreased with HF etching. In contrast, the photoluminescence did not appear until after HF etching times of 20–80 minutes, depending on initial sample porosity. Subsequently, the photoluminescence intensity increased, reached a maximum, and then progressively decreased versus HF etching time. These HF etching results demonstrate that there is no direct correlation between the photoluminescence and the silicon hydrogen surface species.

No Correlation Between Porous Silicon Photoluminescence and Surface Hydrogen Species

1993 ◽  
Vol 298 ◽  
Author(s):  
S.M. Geoqrg ◽  
M.B. Robinson ◽  
A.C. Dillon
Keyword(s):  
Porous Silicon ◽  
Amorphous Silicon ◽  
Thermal Annealing ◽  
Quantum Confinement ◽  
Vacuum Chamber ◽  
Etching Time ◽  
Surface Species ◽  
Initial Sample ◽  
Surface Hydrogen

AbstractThe photoluminescence (PL) of porous silicon has been attributed to quantum confinement, amorphous silicon, or surface species such as hydrogen, polysilanes or siloxene. Our research has tested the early claims that surface hydrogen is responsible for PL. Our initial studies examined the effect of thermal annealing on surface hydrogen and PL in situ in an ultrahigh vacuum chamber. The results showed that the PL decreased between 450–550 whereas H2 was desorbed from surface SiH2 species between 500–575 K. There was no direct correlation between the PL and the loss of SiH2 surface species. Our most recent investigations have monitored PL and surface hydrogen species as a function of HF etching time for electrochemically anodized porous silicon samples that were not initially photoluminescent. While the surface hydrogen species continually decreased versus HF etching time, the photoluminescence did not appear until after HF etching times of 20–80 minutes depending on initial sample porosity. These results again illustrated that there is no direct correlation between the PL and surface hydrogen species.

Effect of etching time in hydrofluoric acid on the structure and morphology of n-type porous silicon

2020 ◽  
Vol 532 ◽  
pp. 147463 ◽  
Author(s):  
Martin Kopani ◽  
Milan Mikula ◽  
Daniel Kosnac ◽  
Jaroslav Kovac ◽  
Michal Trnka ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Hydrofluoric Acid ◽  
Etching Time ◽  
Structure And Morphology

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

1991 ◽  
Vol 256 ◽  
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.

scholarly journals Effect of etching time on characterizations of porous silicon passivated by a nano-silver layer

2020 ◽  
Vol 1529 ◽  
pp. 032106
Author(s):  
Muna E. Raypah ◽  
Naser M. Ahmed ◽  
S.A.M Samsuri ◽  
Shahrom Mahmud
Keyword(s):  
Porous Silicon ◽  
Silver Layer ◽  
Etching Time ◽  
Nano Silver

scholarly journals EFFECT OF ETCHING AS PRE-TREATMENT FOR ELECTROLESS COPPER PLATING ON SILICON WAFER

2017 ◽  
Vol 79 (7) ◽  
Author(s):  
Shazatul Akmaliah Mior Shahidin ◽  
Nor Akmal Fadil ◽  
Mohd Zamri Yusop ◽  
Mohd Nasir Tamin ◽  
Saliza Azlina Osman
Keyword(s):  
Silicon Wafer ◽  
Hydrofluoric Acid ◽  
Copper Film ◽  
Etching Time ◽  
Electroless Copper Plating ◽  
Cross Sectional ◽  
Electroless Process ◽  
Pre Treatment ◽  
Sectional Analysis ◽  
Mechanical Bonding

Metallic coatings, such as copper films can be easily deposited on semiconductor materials like silicon wafer without prior surface pre-treatment using the electroless process. However, the adhesion of the copper film can be very weak and can easily peels off. In this study, the effect of etching in hydrofluoric acid solution as a surface pre-treatment prior to electroless plating on silicon wafer was studied. The etching time in hydrofluoric acid was varied at 1, 3 and 5 minutes in order to investigate the adhesion behaviour of the coating layer. The surface morphology of the electroless plated samples was observed using a field emission scanning electron microscope (FESEM) and the coating thickness was measured using cross sectional analysis. The results showed that longer etching time (5 minutes) produced thicker Cu deposits (8.5μm) than 1 minute etching time (5μm). In addition, by increasing the etching time, the mechanical bonding between the copper film and the substrate is improved.

scholarly journals Acid Etching as Surface Treatment Method for Luting of Glass-Ceramic Restorations, part 1: Acids, Application Protocol and Etching Effectiveness

2018 ◽  
Vol 6 (3) ◽  
pp. 568-573 ◽  
Author(s):  
Emilija Barjaktarova-Valjakova ◽  
Anita Grozdanov ◽  
Ljuben Guguvcevski ◽  
Vesna Korunoska-Stevkovska ◽  
Biljana Kapusevska ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Glass Ceramic ◽  
Hydrofluoric Acid ◽  
Treatment Method ◽  
Acid Etching ◽  
Etching Time ◽  
Ceramic Surface ◽  
Adhesive Luting ◽  
Ceramic Restorations ◽  
Etching Effect

AIM: The purpose of this review is to represent acids that can be used as surface etchant before adhesive luting of ceramic restorations, placement of orthodontic brackets or repair of chipped porcelain restorations. Chemical reactions, application protocol, and etching effect are presented as well.STUDY SELECTION: Available scientific articles published in PubMed and Scopus literature databases, scientific reports and manufacturers' instructions and product information from internet websites, written in English, using following search terms: “acid etching, ceramic surface treatment, hydrofluoric acid, acidulated phosphate fluoride, ammonium hydrogen bifluoride”, have been reviewed.RESULTS: There are several acids with fluoride ion in their composition that can be used as ceramic surface etchants. The etching effect depends on the acid type and its concentration, etching time, as well as ceramic type. The most effective etching pattern is achieved when using hydrofluoric acid; the numerous micropores and channels of different sizes, honeycomb-like appearance, extruded crystals or scattered irregular ceramic particles, depending on the ceramic type, have been detected on the etched surfaces.CONCLUSION: Acid etching of the bonding surface of glass - ceramic restorations is considered as the most effective treatment method that provides a reliable bond with composite cement. Selective removing of the glassy matrix of silicate ceramics results in a micromorphological three-dimensional porous surface that allows micromechanical interlocking of the luting composite.

Etching time effect on optical properties of porous silicon for solar cells fabrication

Optik ◽  
2017 ◽  
Vol 147 ◽  
pp. 343-349 ◽  
Author(s):  
Y. Al-Douri ◽  
N. Badi ◽  
C.H. Voon
Keyword(s):  
Optical Properties ◽  
Solar Cells ◽  
Porous Silicon ◽  
Time Effect ◽  
Etching Time

EFFECT OF ETCHING TIME ON OPTICAL AND MORPHOLOGICAL FEATURES OF N-TYPE POROUS SILICON PREPARED BY PHOTO-ELECTROCHEMICAL METHOD

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Asad A. Thahe ◽  
Noriah Bidin ◽  
Mohammed A. Al-Azawi ◽  
Naser M. Ahmed
Keyword(s):  
Porous Silicon ◽  
Gravimetric Method ◽  
Constant Current ◽  
Etching Time ◽  
Absorption Data ◽  
Time Duration ◽  
Constant Current Density ◽  
Force Microscopy ◽  
Atomic Force ◽  
Structure Properties

Achieving efficient visible photoluminescence from porous-silicon (PSi) is demanding for optoelectronic and solar cells applications. Improving the absorption and emission features of PSi is challenging. Photo-electro-chemical etching assisted formation of PSi layers on n-type (111) silicon (Si) wafers is reported. Samples are prepared at constant current density (~30 mA/cm2) under varying etching times of 10, 15, 20, 25, and 30 min. The influence of etching time duration on the growth morphology and spectral properties are inspected. Room temperature photoluminescence (PL) measurement is performed to determine the optical properties of as-synthesized samples. Sample morphologies are imaged via Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The thickness and porosity of the prepared samples are estimated using the gravimetric method. The emission and absorption data is further used to determine the samples band gap and electronic structure properties. Results and analyzed, interpreted with different mechanisms and compared.  

scholarly journals Porous Silicon Structural Evolution from In-Situ Luminescence and Raman Measurements

1996 ◽  
Vol 431 ◽  
Author(s):  
D. R. Tallant ◽  
M. J. Kelly ◽  
T. R. Guilinger ◽  
R. L. Simpson
Keyword(s):  
Porous Silicon ◽  
Silicon Surface ◽  
Structural Evolution ◽  
Surface Oxidation ◽  
Ethanol Solution ◽  
Nonradiative Recombination ◽  
Photoluminescence Intensity ◽  
Exciton Migration ◽  
Photoluminescence Mechanism

AbstractWe performed in-situ photoluminescence and Raman measurements on an anodized silicon surface in the HF/ethanol solution used for anodization. The porous silicon thereby produced, while resident in HF/ethanol, does not immediately exhibit intense photoluminescence. Intense photoluminescence develops spontaneously in HF/ethanol after 18–24 hours or with replacement of the HF/ethanol with water. These results support a quantum confinement mechanism in which exciton migration to traps and nonradiative recombination dominates the de-excitation pathways until silicon nanocrystals are physically separated and energetically decoupled by hydrofluoric acid etching or surface oxidation. The porous silicon surface, as produced by anodization, shows large differences in photoluminescence intensity and peak wavelength over millimeter distances. Parallel Raman measurements implicate nanometer-size silicon particles in the photoluminescence mechanism.

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