scholarly journals Evidence for quantum confinement in the photoluminescence of porous Si and SiGe

1991 ◽  
Vol 59 (17) ◽  
pp. 2118-2120 ◽  
Author(s):  
S. Gardelis ◽  
J. S. Rimmer ◽  
P. Dawson ◽  
B. Hamilton ◽  
R. A. Kubiak ◽  
...  
Keyword(s):  
Quantum Confinement ◽  
Porous Si

Picosecond Decay Dynamics in Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
T. Matsumoto ◽  
T. Futagi ◽  
H. Mimura ◽  
Y. Kanemitsu
Keyword(s):  
Porous Silicon ◽  
Quantum Confinement ◽  
Streak Camera ◽  
Luminescence Decay ◽  
Experimental Results ◽  
Porous Si ◽  
Emission Energy ◽  
Localized State ◽  
Hydrogen Termination

ABSTRACTPicosecond decay dynamics of luminescent porous silicon has been studied using the second harmonics (SH) of a cw modelocked YLF laser and a synchroscan streak camera. Picosecond luminescence decay shows nonexponential behavior that becomes large with decreasing emission energy. When increasing hydrogen termination on the surface of a Si microcrystal occurs, this picosecond luminescence decay becomes faster. Our experimental results indicate that there are two luminescent states in porous Si : a weak luminescent quantum confinement state and a strong luminescent surface localized state.

Silicon Nanostructures in Si-Based Light-Emithing Devices

1993 ◽  
Vol 298 ◽  
Author(s):  
Fereydoon Namavar ◽  
R.F. Pinizzotto ◽  
H. Yang ◽  
N. Kalkhoran ◽  
P. Maruska
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Silicon Nanostructures ◽  
Porous Si ◽  
Cross Sectional ◽  
Quantum Size ◽  
Visible Wavelengths ◽  
Si Nanostructures

AbstractHigh resolution cross-sectional electron microscopy and electron diffraction of an np heterojunction porous Si device, capable of emitting light at visible wavelengths, clearly indicates the presence of Si nanostructures within the quantum size regime. These results indicate that the quantum confinement effect is at least partially responsible for photoluminescence at visible wavelengths.

Optical properties of porous silicon

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1184-1193 ◽  
Author(s):  
D. J. Lockwood ◽  
G. C. Aers ◽  
L. B. Allard ◽  
B. Bryskiewicz ◽  
S. Charbonneau ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Confinement ◽  
Chemical Dissolution ◽  
Optical Absorption Spectra ◽  
Porous Si ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Si Nanostructures ◽  
Si Films

The optical and structural properties of porous Si films produced by electrochemical and chemical dissolution of Si have been studied by a variety of techniques. Raman scattering and transmission electron microscopy have shown the samples to contain crystalline Si wires and (or) spherites 3–8 nm in diameter and (or) amorphous Si. The optical absorption spectra and the wavelength, temperature, and lifetime dependence of the photoluminescence obtained from most of the samples are entirely consistent with the quantum confinement of excitons in Si nanostructures. Quite different photoluminescence was obtained from other samples composed only of amorphous Si, and this is attributed to the presence of silicon oxyhydride species.

Luminescent Colloidal SI Suspensions from Porous SI

1991 ◽  
Vol 256 ◽  
Author(s):  
Julie L. Heinrich ◽  
Corrine L. Curtis ◽  
Grace M. Credo ◽  
Karen L. Kavanagh ◽  
Michael J. Sailor
Keyword(s):  
Quantum Confinement ◽  
Methylene Chloride ◽  
Colloidal Suspensions ◽  
Porous Si ◽  
Irregular Shapes ◽  
Quantum Confinement Effects ◽  
Transmission Electron ◽  
Si Nanoparticles ◽  
Si Films ◽  
P Type

ABSTRACTA procedure for generating colloidal suspensions of Si exhibiting luminescence, attributed to quantum confinement effects, is described. Samples of n- or p-type Si, that have been electrochemically etched to form porous Si, can be ultrasonically dispersed into methylene chloride, acetonitrile, methanol, toluene, or water solvents, forming a suspension of fine Si particles that luminesce. Transmission electron microscopy analyses show the Si particles to have irregular shapes, with diameters ranging from many microns to nanometers. Luminescent, composite polystyrene/Si films can be made by the addition of polystyrene to a toluene suspension of the Si nanoparticles and casting of the resulting solution.

scholarly journals Photoluminescence of Silicon Nanostructures Formed by Ion Beam Implantation

1992 ◽  
Vol 279 ◽  
Author(s):  
D. A. Redman ◽  
D. M. Follstaedt ◽  
T. Guilinger ◽  
M. Kelly
Keyword(s):  
Quantum Confinement ◽  
Ion Beam ◽  
Subsurface Layer ◽  
Blue Shift ◽  
Nanometer Scale ◽  
Silicon Nanostructures ◽  
Porous Si ◽  
Ion Beam Implantation ◽  
Scale Structures ◽  
Confinement Model

ABSTRACTA new method was used to fabricate nanometer-scale structures in Si for photoluminescence (PL) studies. He ions were implanted to form a dense subsurface layer of small cavities (1–8 nm diameters). The implanted specimens were either annealed in H or anodized with HF to evaluate the quantum confinement model for PL from porous Si. Incomplete passivation apparently prevented PL in the H-annealed specimens. Implantation combined with anodization produced a substantial blue shift relative to anodization alone, which is consistent with quantum confinement.

Spectral characteristics of visible light emission from porous Si: Quantum confinement or impurity effect?

1994 ◽  
Vol 75 (5) ◽  
pp. 2727-2729 ◽  
Author(s):  
V. P. Bondarenko ◽  
V. E. Borisenko ◽  
A. M. Dorofeev ◽  
I. N. Germanenko ◽  
S. V. Gaponenko
Keyword(s):  
Visible Light ◽  
Quantum Confinement ◽  
Light Emission ◽  
Spectral Characteristics ◽  
Impurity Effect ◽  
Porous Si ◽  
Visible Light Emission

scholarly journals Enhancement of Temperature Fluorescence Brightness of Zn@Si Core-Shell Quantum Dots Produced via a Unified Strategy

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3158
Author(s):  
Mohammad S. Almomani ◽  
Naser M. Ahmed ◽  
Marzaini Rashid ◽  
M. K. M. Ali ◽  
H. Akhdar ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement ◽  
Emission Spectra ◽  
Core Shell ◽  
Porous Si ◽  
Top Down ◽  
Bottom Up ◽  
Orange Yellow ◽  
Red Luminescence ◽  
Bright Blue

Despite many dedicated efforts, the fabrication of high-quality ZnO-incorporated Zinc@Silicon (Zn@Si) core–shell quantum dots (ZnSiQDs) with customized properties remains challenging. In this study, we report a new record for the brightness enhancement of ZnSiQDs prepared via a unified top-down and bottom-up strategy. The top-down approach was used to produce ZnSiQDs with uniform sizes and shapes, followed by the bottom-up method for their re-growth. The influence of various NH4OH contents (15 to 25 µL) on the morphology and optical characteristics of ZnSiQDs was investigated. The ZnSiQDs were obtained from the electrochemically etched porous Si (PSi) with Zn inclusion (ZnPSi), followed by the electropolishing and sonication in acetone. EFTEM micrographs of the samples prepared without and with NH4OH revealed the existence of spherical ZnSiQDs with a mean diameter of 1.22 to 7.4 nm, respectively. The emission spectra of the ZnSiQDs (excited by 365 nm) exhibited bright blue, green, orange-yellow, and red luminescence, indicating the uniform morphology related to the strong quantum confinement ZnSiQDs. In addition, the absorption and emission of the ZnSiQDs prepared with NH4OH were enhanced by 198.8% and 132.6%, respectively. The bandgap of the ZnSiQDs conditioned without and with NH4OH was approximately 3.6 and 2.3 eV, respectively.

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