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

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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Strong Enhancement of Porous Silicon Photoluminescence by Dry Photo-Chemical Surface Treatment

MRS Proceedings ◽

10.1557/proc-638-f5.23.1 ◽

2000 ◽

Vol 638 ◽

Cited By ~ 1

Author(s):

S. Stolyarova ◽

A. El-Bahar ◽

Y. Nemirovsky

Keyword(s):

Porous Silicon ◽

Surface Treatment ◽

Oxide Layer ◽

Silicon Surface ◽

Native Oxide ◽

Photoluminescence Intensity ◽

Chemical Surface ◽

Porous Silicon Surface ◽

Crystalline Oxide ◽

Photoluminescence Enhancement

AbstractPorous silicon has been subjected to NF3/UV photochemical surface treatment in the range of 300-4000C. This treatment is found to enhance strongly the photoluminescence of porous silicon by couple orders of magnitude. The effect of photoluminescence enhancement has been observed only when the NF3 treated porous silicon was exposed to air environment. The photoluminescence intensity continued to grow with the aging time in air, even at the room temperature. Using atomic force microscope, scanning electron microscope and Auger measurements, it is found that the photoluminescence enhancement correlated with the formation of crystalline oxide layer at the porous silicon surface. This oxide layer SiOx (x≅2) is much more stoichiometric as compared to the native oxide SiOx (x≅1) covering the reference porous silicon surface (not treated by NF3). The rapid growth of the SiO2 layer is supposed to be due to the NF3/UV photo-thermal etching of the as-formed native oxide as well as to the cleaning and passivation of the porous silicon surface with fluorine.

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In-situ FT-IR studies of porous silicon surface reactions

Journal of Molecular Structure ◽

10.1016/0022-2860(95)08721-7 ◽

1995 ◽

Vol 349 ◽

pp. 109-112 ◽

Cited By ~ 2

Author(s):

R. Dietrich ◽

J. Grobe ◽

H. Feld

Keyword(s):

Porous Silicon ◽

Silicon Surface ◽

Surface Reactions ◽

Porous Silicon Surface ◽

Ir Studies ◽

Ft Ir

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Investigation of Chemical Adsorbate Effects on Blue and Red Emitting Porous Silicon Samples

MRS Proceedings ◽

10.1557/proc-358-393 ◽

1994 ◽

Vol 358 ◽

Author(s):

Julie M. Rehm ◽

George L. McLendon ◽

Leonid Tsybeskov ◽

Philippe M. Fauchet

Keyword(s):

Steady State ◽

Porous Silicon ◽

Surface Passivation ◽

Chemical Exposure ◽

Nonradiative Recombination ◽

Photoluminescence Intensity ◽

Time Resolved ◽

Optical Effects ◽

Solvent Molecules ◽

Time Resolved Photoluminescence

ABSTRACTWe have investigated the sensitivity of blue (PLmax = 480 nm) and red (PLmax = 660 nm) emitting porous silicon samples to various chemical adsorbates. Steady-state and time-resolved photoluminescence measurements and FTIR spectroscopy were employed to characterize the photophysical and optical effects induced by chemical exposure. The red samples, which are hydrogen terminated, exhibit quenching and recovery of photoluminescence intensity and broadening of the Si-Hx stretch bands upon exposure to liquid methanol. This behavior is attributed to the ability of the Si-Hx specie on the surface of the PSI to interact with the solvent molecules which temporarily traps the electrons and causes PL loss and Si-Hx broadening. The blue samples, which are oxygen terminated, display similar sensitivity to methanol. This sensitivity is attributed to the solvent's ability to change the surface passivation and thereby introduce competitive radiative and nonradiative recombination channels. The origin of the blue PL is discussed.

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Morphological evolution of the porous silicon surface for different etching time and current density in hf-ethanol solution

Revista Brasileira de Aplicações de Vácuo ◽

10.17563/rbav.v34i3.989 ◽

2015 ◽

Vol 34 (3) ◽

pp. 89

Author(s):

Miguel Angelo Do Amaral Junior ◽

Belchior Elton Lima da Silva ◽

Neidenêi Gomes Ferreira ◽

Antonio Fernando Beloto ◽

Maurício Ribeiro Baldan

Keyword(s):

Porous Silicon ◽

Current Density ◽

Silicon Surface ◽

Morphological Evolution ◽

Ethanol Solution ◽

Etching Time ◽

Porous Silicon Surface

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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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Porous silicon structural evolution from in-situ luminescence and Raman measurements

10.2172/231693 ◽

1996 ◽

Author(s):

D.R. Tallant ◽

M.J. Kelly ◽

T.R. Guilinger ◽

R.L. Simpson

Keyword(s):

Porous Silicon ◽

Structural Evolution

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Profile Imaging of Silicon Surface Reconstructions

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118229 ◽

1985 ◽

Vol 43 ◽

pp. 262-263

Author(s):

O.L. Krivanek ◽

G.J. Wood

Keyword(s):

Electron Microscopy ◽

Surface Structure ◽

Structure Determination ◽

Silicon Surface ◽

Good Resolution ◽

Surface Reconstructions ◽

Bulk Structure ◽

Point To Point ◽

The Relationship

Electron microscopy at 0.2nm point-to-point resolution, 10-10 torr specimei region vacuum and facilities for in-situ specimen cleaning presents intere; ing possibilities for surface structure determination. Three methods for examining the surfaces are available: reflection (REM), transmission (TEM) and profile imaging. Profile imaging is particularly useful because it giv good resolution perpendicular as well as parallel to the surface, and can therefore be used to determine the relationship between the surface and the bulk structure.

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In-Situ Study of NiO Growth on Textured Nickel Tape Using Environmental Scanning Electron Microscope (ESEM) and Hot Stage

Microscopy and Microanalysis ◽

10.1017/s1431927600032451 ◽

2001 ◽

Vol 7 (S2) ◽

pp. 1276-1277

Author(s):

Y. Akin ◽

R.E. Goddard ◽

W. Sigmund ◽

Y.S. Hascicek

Keyword(s):

Buffer Layer ◽

Lattice Mismatch ◽

Sol Gel ◽

Surface Oxidation ◽

Dip Coating ◽

Buffer Layers ◽

Superconducting Film ◽

Environmental Scanning ◽

Cold Rolling And Annealing

Deposition of highly textured ReBa2Cu3O7−δ (RBCO) films on metallic substrates requires a buffer layer to prevent chemical reactions, reduce lattice mismatch between metallic substrate and superconducting film layer, and to prevent diffusion of metal atoms into the superconductor film. Nickel tapes are bi-axially textured by cold rolling and annealing at appropriate temperature (RABiTS) for epitaxial growth of YBa2Cu3O7−δ (YBCO) films. As buffer layers, several oxide thin films and then YBCO were coated on bi-axially textured nickel tapes by dip coating sol-gel process. Biaxially oriented NiO on the cube-textured nickel tape by a process named Surface-Oxidation- Epitaxy (SEO) has been introduced as an alternative buffer layer. in this work we have studied in situ growth of nickel oxide by ESEM and hot stage.Representative cold rolled nickel tape (99.999%) was annealed in an electric furnace under 4% hydrogen-96% argon gas mixture at 1050°C to get bi-axially textured nickel tape.

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