scholarly journals EFFECT OF PHONON CONFINEMENT AND STRAIN ON RAMAN SPECTRA FROM LIGHT-EMITTING POROUS SILICON

1994 ◽  
Vol 43 (3) ◽  
pp. 494
Author(s):  
YANG MIN ◽  
HUANG DA-MING ◽  
HAO PING-HAI ◽  
ZHANG FU-LONG ◽  
HOU XIAO-YUAN ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Raman Spectra ◽  
Phonon Confinement ◽  
Light Emitting

Phonon confinement effects in Raman spectra of porous silicon at non-resonant excitation condition

2014 ◽  
Vol 45 (6) ◽  
pp. 470-475 ◽  
Author(s):  
Marin Kosović ◽  
Ozren Gamulin ◽  
Maja Balarin ◽  
Mile Ivanda ◽  
Vedran Đerek ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Raman Spectra ◽  
Resonant Excitation ◽  
Excitation Condition ◽  
Phonon Confinement ◽  
Confinement Effects

Analysis of the Structure of Light-emitting Porous Silicon by Raman Scattering

1991 ◽  
Vol 256 ◽  
Author(s):  
Zhifeng Sui ◽  
Patrick P. Leong ◽  
Irving P. Herman ◽  
Gregg S. Higashi ◽  
Henryk Temkin
Keyword(s):  
Porous Silicon ◽  
Room Temperature ◽  
Crystalline Silicon ◽  
Silicon Film ◽  
Characteristic Dimension ◽  
Raman Shift ◽  
Phonon Confinement ◽  
Island Size ◽  
Light Emitting ◽  
Silicon Islands

AbastracRaman spectra from a thick porous silicon film (∼100 μm) that strongly emits in the visible (∼ 6350 Å) at room temperature are obtained. An asymmetric peak with a Raman shift of ∼ 508 - 510 cm−1 and a width of ∼ 40 cm−1 is seen in every spectrum. This Raman feature resembles that of μc-Si, suggesting that the local structure of the porous silicon is a network of interconnected crystalline silicon islands with the island size in the nanometer range., and that the, shape of the islands is more sphere-like than rod-like. The characteristic dimension of the islands in these porous silicon films is estimated to be ∼ 2.5 - 3.0 nm on the basis of an empirical model calculation of phonon confinement.

New Results on Electroluminescence from Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
Peter Steiner ◽  
Frank Kozlowski ◽  
Hermann Sandmaier ◽  
Walter Lang
Keyword(s):  
Porous Silicon ◽  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Green Light ◽  
Light Emitting ◽  
Porous Region ◽  
First Results

ABSTRACTFirst results on light emitting diodes in porous silicon were reported in 1991. They showed a quantum efficiency of 10-7 to 10-5 and an orange spectrum. Over the last year some progress was achieved:- By applying UV-light during the etching blue and green light emitting diodes in porous silicon are fabricated.- When a p/n junction is realized within the porous region, a quantum efficiency of 10-4 is obtained.

LUMINESCENCE BEHAVIOR AND MECHANISM OF LIGHT-EMITTING POROUS SILICON

1994 ◽  
Vol 08 (02) ◽  
pp. 69-92 ◽  
Author(s):  
XUN WANG
Keyword(s):  
Porous Silicon ◽  
Blue Light ◽  
Light Emission ◽  
Energy State ◽  
Surface Recombination Velocity ◽  
Luminescence Spectroscopy ◽  
Carrier Injection ◽  
Blue Light Emission ◽  
Light Emitting ◽  
Si Nanostructures

In this review article, we give a new insight into the luminescence mechanism of porous silicon. First, we observed a “pinning” characteristic of photoluminescent peaks for as-etched porous silicon samples. It was explained as resulting from the discontinuous variation of the size of Si nanostructures, i.e. the size quantization. A tight-binding calculation of the energy band gap widening versus the dimension of nanoscale Si based on the closed-shell Si cluster model agrees well with the experimental observations. Second, the blue-light emission from porous silicon was achieved by using boiling water treatment. By investigating the luminescence micrographic images and the decaying behaviors of PL spectra, it has been shown that the blue-light emission is believed to be originated from the porous silicon skeleton rather than the surface contaminations. The conditions for achieving blue light need proper size of Si nanostructures, low-surface recombination velocity, and mechanically strong skeleton. The fulfillment of these conditions simultaneously is possible but rather critical. Third, the exciton dynamics in light-emitting porous silicon is studied by using the temperature-dependent and picosecond time-resolved luminescence spectroscopy. A direct evidence of the existence of confined excitons induced by the quantum size effect has been revealed. Two excitation states are found to be responsible for the visible light emission, i.e. a higher lying energy state corresponding to the confined excitons in Si nanostructures and a lower lying state related with surfaces of Si wires or dots. A picture of the carrier transfer between the quantum confined state and the surface localized state has been proposed. Finally, we investigated the transient electroluminescence behaviors of Au/porous silicon/Si/Al structure and found it is very similar to that of an ordinary p-n junction light-emitting diode. The mechanism of electroluminescence is explained as the carrier injection through the Au/porous silicon Schotky barrier and the porous silicon/p-Si heterojunction into the corrugated Si wires, where the radiative recombination of carriers occurs.

scholarly journals Depth-Resolved Microspectroscopy of Porous Silicon Multilayers

1999 ◽  
Vol 588 ◽  
Author(s):  
S. Manotas ◽  
F. Agulló-Rueda ◽  
J. D. Moreno ◽  
R. J. Martín-Palma ◽  
R. Guerrero-Lemus ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Quantum Confinement ◽  
Silicon Nanocrystals ◽  
Phonon Frequency ◽  
Lattice Mismatch ◽  
High Porosity ◽  
Phonon Confinement ◽  
Heating Effects ◽  
Average Size ◽  
Good Agreement

AbstractWe have measured micro-photoluminescence (PL) and micro-Raman spectra on the cross section of porous silicon multilayers to sample different layer depths. We find noticeable differences in the spectra of layers with different porosity, as expected from the quantum confinement of electrons and phonons in silicon nanocrystals with different average sizes. The PL emission band gets stronger, blue shifts, and narrows at the high porosity layers. The average size can be estimated from the shift. The Raman phonon band at 520 cm−1 weakens and broadens asymmetrically towards the low energy side. The line shape can be related quantitatively with the average size by the phonon confinement model. To get a good agreement with the model we add a band at around 480 cm−1, which has been attributed to amorphous silicon. We also have to leave as free parameters the bulk silicon phonon frequency and its line width, which depend on temperature and stress. We reduced laser power to eliminate heating effects. Then we use the change of frequency with depth to monitor the stress. At the interface with the substrate we find a compressive stress in excess of 10 kbar, which agrees with the reported lattice mismatch. Finally, average sizes are larger than those estimated from PL.

Porous silicon light-emitting diodes – mechanisms in the operation

2001 ◽  
Vol 17 (1-2) ◽  
pp. 111-116 ◽  
Author(s):  
K. Molnár ◽  
T. Mohácsy ◽  
M. Ádám ◽  
I. Bársony
Keyword(s):  
Porous Silicon ◽  
Light Emitting Diodes ◽  
Light Emitting

Light emitting porous silicon diode based on a silicon/porous silicon heterojunction

1999 ◽  
Vol 86 (11) ◽  
pp. 6474-6482 ◽  
Author(s):  
L. Pavesi ◽  
R. Chierchia ◽  
P. Bellutti ◽  
A. Lui ◽  
F. Fuso ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Light Emitting ◽  
Silicon Diode

A phenomenological investigation on porous silicon electroluminescence

1993 ◽  
Vol 298 ◽  
Author(s):  
P. Steiner ◽  
W. Lang ◽  
F. Kozlowski ◽  
H. Sandmaier
Keyword(s):  
Porous Silicon ◽  
Light Emitting Diodes ◽  
Phenomenological Theory ◽  
Electroluminescence Spectrum ◽  
Light Emitting

AbstractThe processing of light emitting diodes in porous silicon with green/blue electroluminescence spectrum is described. The spectral behavicur and the degradation are investigated. A phenomenological theory for the luminescence is given.

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