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On the nature of the stretched exponential photoluminescence decay for silicon nanocrystals.

Zatryb G, Podhorodecki A, Misiewicz J, Cardin J, Gourbilleau F - Nanoscale Res Lett (2011)

Bottom Line: It was found that photoluminescence decay is strongly non-single exponential and can be described by the stretched exponential function.It was also shown that effective decay rate probability density function may be recovered by means of Stehfest algorithm.Moreover, it was proposed that the observed broadening of obtained decay rate distributions reflects the disorder in the samples.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland. artur.p.podhorodecki@pwr.wroc.pl.

ABSTRACT
The influence of hydrogen rate on optical properties of silicon nanocrystals deposited by sputtering method was studied by means of time-resolved photoluminescence spectroscopy as well as transmission and reflection measurements. It was found that photoluminescence decay is strongly non-single exponential and can be described by the stretched exponential function. It was also shown that effective decay rate probability density function may be recovered by means of Stehfest algorithm. Moreover, it was proposed that the observed broadening of obtained decay rate distributions reflects the disorder in the samples.

No MeSH data available.


Related in: MedlinePlus

Absorption spectra calculated on the basis of the reflectance and transmittance measurements. The left axis shows long exponential tails in the absorption edge. The right axis shows curves used for estimating the band gap according to the Tauc formula. The blue-shift of the absorption edge may be observed with increasing rH.
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Figure 2: Absorption spectra calculated on the basis of the reflectance and transmittance measurements. The left axis shows long exponential tails in the absorption edge. The right axis shows curves used for estimating the band gap according to the Tauc formula. The blue-shift of the absorption edge may be observed with increasing rH.

Mentions: Figure 2 shows the absorption (α) spectra calculated from reflectance (R) and transmittance (T) measurements according to the equation α ∝ -ln(T/(1 - R)2) which allows us to deal with disturbing interference patterns [17]. For the higher energy part of the spectra, the Tauc formula (αE) = A(E - Eg)m was used to estimate the optical band gap (Eg). The best fit to the experimental data was obtained for m = 1/2, which corresponds to direct allowed transition. It may also be noted that the absorption edge is significantly blue-shifted from 3.76 eV for rH = 10% to 4.21 eV for rH = 50%. The observed blue-shift of absorption edge may be related to quantum confinement effect which was discussed by us in more details elsewhere [16].


On the nature of the stretched exponential photoluminescence decay for silicon nanocrystals.

Zatryb G, Podhorodecki A, Misiewicz J, Cardin J, Gourbilleau F - Nanoscale Res Lett (2011)

Absorption spectra calculated on the basis of the reflectance and transmittance measurements. The left axis shows long exponential tails in the absorption edge. The right axis shows curves used for estimating the band gap according to the Tauc formula. The blue-shift of the absorption edge may be observed with increasing rH.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211150&req=5

Figure 2: Absorption spectra calculated on the basis of the reflectance and transmittance measurements. The left axis shows long exponential tails in the absorption edge. The right axis shows curves used for estimating the band gap according to the Tauc formula. The blue-shift of the absorption edge may be observed with increasing rH.
Mentions: Figure 2 shows the absorption (α) spectra calculated from reflectance (R) and transmittance (T) measurements according to the equation α ∝ -ln(T/(1 - R)2) which allows us to deal with disturbing interference patterns [17]. For the higher energy part of the spectra, the Tauc formula (αE) = A(E - Eg)m was used to estimate the optical band gap (Eg). The best fit to the experimental data was obtained for m = 1/2, which corresponds to direct allowed transition. It may also be noted that the absorption edge is significantly blue-shifted from 3.76 eV for rH = 10% to 4.21 eV for rH = 50%. The observed blue-shift of absorption edge may be related to quantum confinement effect which was discussed by us in more details elsewhere [16].

Bottom Line: It was found that photoluminescence decay is strongly non-single exponential and can be described by the stretched exponential function.It was also shown that effective decay rate probability density function may be recovered by means of Stehfest algorithm.Moreover, it was proposed that the observed broadening of obtained decay rate distributions reflects the disorder in the samples.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland. artur.p.podhorodecki@pwr.wroc.pl.

ABSTRACT
The influence of hydrogen rate on optical properties of silicon nanocrystals deposited by sputtering method was studied by means of time-resolved photoluminescence spectroscopy as well as transmission and reflection measurements. It was found that photoluminescence decay is strongly non-single exponential and can be described by the stretched exponential function. It was also shown that effective decay rate probability density function may be recovered by means of Stehfest algorithm. Moreover, it was proposed that the observed broadening of obtained decay rate distributions reflects the disorder in the samples.

No MeSH data available.


Related in: MedlinePlus