Effect of γ-Irradiation on Photoluminescence of Porous Silicon

1995 ◽  
Vol 405 ◽  
Author(s):  
E. V. Astrova ◽  
V. V. Emtsev ◽  
A. A. Lebedev ◽  
D. S. Poloskin ◽  
A. D. Remenyuk ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Gamma Irradiation ◽  
Ir Absorption ◽  
Atmospheric Conditions ◽  
Γ Irradiation ◽  
Light Emitting ◽  
Evacuated Tubes ◽  
Pl Intensity ◽  
Higher Doses ◽  
Absorption Measurements

AbstractProperties of Porous Silicon (PS) subjected to gamma irradiation in an air ambient and in vacuum have been studied. Gamma-irradiation was carried out in usual room atmosphere, and in evacuated tubes. The samples of porous silicon were investigated by means of photoluminescence (PL) and infrared (IR) absorption. For the samples irradiated under atmospheric conditions, the PL intensity increases by several times as the dose increases up to 1019photons/cm2 and after that point it starts to go down. For a dose of ˜9.1019photons/cm2 the PL intensity falls by a factor of ˜50. The position of the spectrum maximum does not change, but the half-width of the spectrum increases by 2 or 3 times. In the case of gamma-irradiation in vacuum the PL intensity gradually decreases with increasing dose. IR absorption measurements showed variations of the intensity of Si-H and Si-O bands with the irradiation dose. Enhancement of PL at lower doses has been explained by irradiation assisted oxidation of PS at atmospheric conditions and its degradation at higher doses by suppresion of the light-emitting centers.

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.

Solid Parahydrogen Thickness Revisited

2019 ◽  
Vol 73 (12) ◽  
pp. 1403-1408 ◽  
Author(s):  
Mario E. Fajardo
Keyword(s):  
Systematic Error ◽  
Absorption Spectroscopy ◽  
Ir Absorption ◽  
Spectroscopy Data ◽  
Previous Approach ◽  
Polarization Effects ◽  
Peak Intensity ◽  
Absorption Measurements

We report updated infrared (IR) absorption measurements on vapor-deposited cryogenic parahydrogen (pH2) solids that indicate a ≈10% systematic error in our previous approach for determining a pH2 solid's thickness (S. Tam and M.E. Fajardo. Appl. Spectrosc. 2001. 55(12): 1634-1644). We provide corrected values for the integrated absorption intensities of the Q1(0)+S0(0) and S1(0)+S0(0) bands calculated over the 4495–4520 cm−1 and 4825–4855 cm−1 regions, respectively. New polarized IR absorption spectroscopy data demonstrate the insensitivity to polarization effects of the peak intensity of the QR(0) phonon sideband near 4228 cm−1. This feature provides an even quicker way for determining the thickness of a pH2 solid than via the integrated absorptions.

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.

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

scholarly journals Влияние условий роста и уровня легирования на кинетику люминесценции слоев Ge : Sb, выращенных на кремнии

2020 ◽  
Vol 54 (7) ◽  
pp. 685
Author(s):  
Д.В. Юрасов ◽  
Н.А. Байдакова ◽  
А.Н. Яблонский ◽  
А.В. Новиков
Keyword(s):  
Doping Level ◽  
Room Temperature ◽  
Carrier Lifetime ◽  
Growth Conditions ◽  
Published Data ◽  
Rapid Thermal Anneal ◽  
Time Resolved ◽  
Light Emitting ◽  
Pl Intensity ◽  
Time Resolved Photoluminescence

Light-emitting properties of Ge-on-Si(001) layers doped by Sb were studied by stationary and time-resolved photoluminescence (PL) at room temperature. It was obtained that the PL intensity of n-Ge/Si(001) structures is maximized when the doping level is close to the equilibrium solubility of Sb in Ge (~1019 cm-3) which is in accordance with the previously published data. Time-resolved studies of the direct-related PL signal have shown that both the donor density and the growth conditions of doped layer, in particular, the growth temperature influence the PL kinetics. It was obtained that the increase of doping level leads to the decrease of the characteristic carrier lifetime. Moreover, usage of low growth temperatures which is needed to form the doped n-Ge layers also results in shortening of the carrier lifetime as compared with Ge layers grown at high temperatures. It was found that rapid thermal anneal at proper conditions could partially compensate the above mentioned detrimental effects and lead to the increase of both the PL intensity and carrier lifetime.

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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