Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix
The results of experimental researches of photoluminescence (PL) spectra in Si nanocluster structures obtained by implantation of silicon ions to SiO₂-Si structures with high-temperature (1100 °C) and following low-temperature annealings in various regimes are given. We have found that additional...
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Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
2008
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| Zitieren: | Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix / I. Khatsevich, V. Melnik, V. Popov, B. Romanyuk, V. Fedulov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2008. — Т. 11, № 4. — С. 352-355. — Бібліогр.: 17 назв. — англ. |
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nasplib_isofts_kiev_ua-123456789-1190682025-06-03T16:25:24Z Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix Khatsevich, I. Melnik, V. Popov, V. Romanyuk, B. Fedulov, V. The results of experimental researches of photoluminescence (PL) spectra in Si nanocluster structures obtained by implantation of silicon ions to SiO₂-Si structures with high-temperature (1100 °C) and following low-temperature annealings in various regimes are given. We have found that additional low-temperature treatments in definite regimes result in substantial increase of the PL intensity, thus a maximum effect is observed after annealing in air. The possible mechanisms of the obtained effects are discussed. Those are based on supposition about the dominating contribution of luminescence through the electronic states on SiO₂-Si nanoclaster interfaces, which is related to defect and impurity complexes. It has been shown that growth of the PL intensity is governed by two effects: generation of new centers of radiative recombination on the nanocrystal-dielectric matrix interfaces, and passivation of nonradiative recombination centers. This work was supported by the MES of Ukraine (Grant # M/175-2007). 2008 Article Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix / I. Khatsevich, V. Melnik, V. Popov, B. Romanyuk, V. Fedulov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2008. — Т. 11, № 4. — С. 352-355. — Бібліогр.: 17 назв. — англ. 1560-8034 PACS 61.72.T, 78.55.M https://nasplib.isofts.kiev.ua/handle/123456789/119068 en Semiconductor Physics Quantum Electronics & Optoelectronics application/pdf Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
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English |
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The results of experimental researches of photoluminescence (PL) spectra in
Si nanocluster structures obtained by implantation of silicon ions to SiO₂-Si structures
with high-temperature (1100 °C) and following low-temperature annealings in various
regimes are given. We have found that additional low-temperature treatments in definite
regimes result in substantial increase of the PL intensity, thus a maximum effect is
observed after annealing in air. The possible mechanisms of the obtained effects are
discussed. Those are based on supposition about the dominating contribution of
luminescence through the electronic states on SiO₂-Si nanoclaster interfaces, which is
related to defect and impurity complexes. It has been shown that growth of the PL
intensity is governed by two effects: generation of new centers of radiative
recombination on the nanocrystal-dielectric matrix interfaces, and passivation of nonradiative
recombination centers. |
| format |
Article |
| author |
Khatsevich, I. Melnik, V. Popov, V. Romanyuk, B. Fedulov, V. |
| spellingShingle |
Khatsevich, I. Melnik, V. Popov, V. Romanyuk, B. Fedulov, V. Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix Semiconductor Physics Quantum Electronics & Optoelectronics |
| author_facet |
Khatsevich, I. Melnik, V. Popov, V. Romanyuk, B. Fedulov, V. |
| author_sort |
Khatsevich, I. |
| title |
Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix |
| title_short |
Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix |
| title_full |
Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix |
| title_fullStr |
Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix |
| title_full_unstemmed |
Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix |
| title_sort |
effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized si nanocrystals in sio₂ matrix |
| publisher |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| publishDate |
2008 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/119068 |
| citation_txt |
Effect of low-temperature treatments on photoluminescence enhancement of ion-beam synthesized Si nanocrystals in SiO₂ matrix / I. Khatsevich, V. Melnik, V. Popov, B. Romanyuk, V. Fedulov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2008. — Т. 11, № 4. — С. 352-355. — Бібліогр.: 17 назв. — англ. |
| series |
Semiconductor Physics Quantum Electronics & Optoelectronics |
| work_keys_str_mv |
AT khatsevichi effectoflowtemperaturetreatmentsonphotoluminescenceenhancementofionbeamsynthesizedsinanocrystalsinsio2matrix AT melnikv effectoflowtemperaturetreatmentsonphotoluminescenceenhancementofionbeamsynthesizedsinanocrystalsinsio2matrix AT popovv effectoflowtemperaturetreatmentsonphotoluminescenceenhancementofionbeamsynthesizedsinanocrystalsinsio2matrix AT romanyukb effectoflowtemperaturetreatmentsonphotoluminescenceenhancementofionbeamsynthesizedsinanocrystalsinsio2matrix AT fedulovv effectoflowtemperaturetreatmentsonphotoluminescenceenhancementofionbeamsynthesizedsinanocrystalsinsio2matrix |
| first_indexed |
2025-11-25T18:24:26Z |
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2025-11-25T18:24:26Z |
| _version_ |
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| fulltext |
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 4. P. 352-355.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
352
PACS 61.72.T, 78.55.M
Effect of low-temperature treatments on photoluminescence
enhancement of ion-beam synthesized
Si nanocrystals in SiO2 matrix
I. Khatsevich, V. Melnik, V. Popov, B. Romanyuk, V. Fedulov
V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine
41, prospect Nauky, 03028 Kyiv, Ukraine
E-mail: romb@isp.kiev.ua; phone/fax: +38(044)-525-57-24
Abstract. The results of experimental researches of photoluminescence (PL) spectra in
Si nanocluster structures obtained by implantation of silicon ions to SiO2-Si structures
with high-temperature (1100 °C) and following low-temperature annealings in various
regimes are given. We have found that additional low-temperature treatments in definite
regimes result in substantial increase of the PL intensity, thus a maximum effect is
observed after annealing in air. The possible mechanisms of the obtained effects are
discussed. Those are based on supposition about the dominating contribution of
luminescence through the electronic states on SiO2-Si nanoclaster interfaces, which is
related to defect and impurity complexes. It has been shown that growth of the PL
intensity is governed by two effects: generation of new centers of radiative
recombination on the nanocrystal-dielectric matrix interfaces, and passivation of non-
radiative recombination centers.
Keywords: photoluminescence, ion implantation, annealing, nanocluster.
Manuscript received 23.09.08; accepted for publication 20.10.08; published online 11.11.08.
1. Introduction
Luminescent properties of silicon nanoclusters built in
dielectric matrices (SiO2, Si3N4, silicon oxynitride) are
investigated in recent years through perspectives of
application of these structures in opto- and micro-
electronics [1-3]. Standard procedures for fabrication of
experimental samples are: ion implantation of silicon in
SiO2 layer [3, 4]; deposition of SiOx or silicon oxynitride
layers by different methods with a following high-
temperature (1000 to 1150 °C) thermal annealing [5, 6].
To improve luminescent properties of the obtained
structures, the additional impurity doping (nitrogen,
carbon, rare-earth elements) [3, 7, 8], passivation of Pb-
centers by hydrogen [9, 10], or additional low-
temperature treatments [11, 12] are used. It is also
shown that the annealing atmosphere affects on intensity
and position of a luminescence band [13-15].
When explaining the physical mechanisms of
additional low-temperature treatments and/or atmo-
sphere influence, most of the authors use the models of
luminescence via charge carrier recombination in a
nanocluster (quantum model) [4, 5, 10], or through the
electronic states at the Si nanocluster-dielectric matrix
interfaces [2, 6, 9].
In [11], to explain the effect of PL intensity
increase at low-temperature annealing, the model of
thermodonor center generation at the nanocluster-
dielectric matrix interface was proposed, which could be
taken into account for the PL bands within the range of
1.5 to 1.75 eV. However, up to now there is no common
model of interface or thermodonor centers, and also
explanation of the low-temperature treatment influence
on the intensity and position of the luminescence band.
In this work, we try to discriminate the mechanisms
of additional low-temperature treatment influence on PL
of the Si nanocluster structures created by ion
implantation of silicon into a SiO2 matrix: passivation of
the non-radiative recombination centers or generation of
additional centers for radiative recombination. The use
of wide set of annealing ambient (nitrogen, argon,
hydrogen, mixture of oxygen and nitrogen) and
annealing regimes is the feature of our experiments.
2. Experimental
p-Si (100) (10 Ohm·cm) wafers were oxidized in the
atmosphere of wet oxygen to the SiO2 thickness of
350 nm. Si+ ion implantation in SiO2 with the energy E =
100 keV and dose interval of 2×1016 to 1.2×1017 cm–2
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 4. P. 352-355.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
353
was performed. For formation of the silicon nanoclusters
all the samples were annealed at the temperature of
1100 °С during 20 min in atmosphere of inert gas (Ar)
or nitrogen. Then structures with formed silicon
nanoclusters were exposed to low-temperature treat-
ments at the temperatures within the interval of 400 to
850 °C in various ambients (vacuum, nitrogen, hydro-
gen, oxygen, and mixtures of those).
PL spectra were measured at room temperature and
excitation by the continuous-mode solid-state laser
(473 nm).
3. Results
PL spectra of the SiO2/Si samples implanted by different
doses of Si ions after high-temperature forming are
shown in Fig. 1.
At the small dose of implanted silicon (2×1016 cm–2),
after the high-temperature annealing in Ar the PL bands
are not observed. Weak PL band near the wavelength
λ = 700 nm is observed after annealing in nitrogen. At
higher Si+ doses PL is observed in a longwave region.
With increasing implanted silicon dose, the PL band
shifts to the longwave side, and the PL intensity
decreases. In the samples annealed in N2 ambient, the PL
intensity is higher, and the band position is displaced to
the shortwave range, as compared with the similar
samples formed in Ar. In addition, in the PL spectrum of
the samples formed in nitrogen, there exists a weak PL
band at the shortwave region (~ 560 nm) that is not
observed after formation in an inert atmosphere.
The maximum photoluminescence intensity was
observed for the samples with the dose of Si
implantation of 9.5×1016 cm–2 in all the annealing
regimes. So, the given below results concerning the
influence of the additional low-temperature annealing on
the PL intensity are related to the samples with this
implantation dose and forming annealing at 1100 °C,
20 min, Ar or N2 ambient.
Photoluminescence spectra of the samples after
combined annealing (forming high-temperature one, and
subsequent low-temperature at 450 °C in air) are shown
in Fig. 2.
The PL intensity after low-temperature annealing is
substantially higher (by 10 times for the samples formed
in Ar, and by 4 times – in N2), and PL peak is shifted a
little to the longwave side (PL maximum is close to
790 nm). In the shortwave region, after the low-
temperature annealing the new PL band with its peak at
590 nm appears for all the samples. The intensity of this
band increases with the implanted silicon dose.
PL spectra of the samples after annealing in
hydrogen (480 °C, 2 h) are shown in Fig. 3. Annealing in
hydrogen leads to PL growth both after a forming
annealing, and after a low-temperature annealing in air.
The most intensive luminescence is observed for
the samples formed in Ar, the annealed at low
temperature in air, and then annealed in hydrogen.
600 700 800 900 1000 1100
10
100
1000
P
L
in
te
ns
ity
, a
.u
.
λ, nm
in N2 Doze Si+
2x1016 cm-2
9.5x1016 cm-2
1.2x1017 cm-2
in Ag
9.5x1016 cm-2
Fig. 1. PL spectra of the SiO2/Si samples implanted with Si at
different doses, after the high-temperature forming annealing
(1100 °С, 20 min, Ar or N2).
Additional temperature treatment within the range
of 500 to 800 °C did not result in substantial increase
of PL.
The PL integral intensity after the different stages
of the structure annealing is given in Table.
4. Discussion
As it was shown in the set of papers [2, 4, 9, 16], in the
SiO2-Si structures implanted by silicon, during the
following high-temperature annealing, Si nanoclusters
with sizes of 1 to 6 nm are formed (depending on the
implantation dose and annealing time). With the
implantation dose increase, the nanocluster
concentration increases, and it leads to growth of the PL
intensity (regardless of the mechanism of radiative
recombination of non-equilibrium charge carriers).
Growth of the large clusters goes at the expense of decay
of the small ones. It results in reduction of the cluster
concentration, the total area of the SiO2-Si boundaries
diminishes too, which leads to reduction of the PL
intensity both in the case of radiative recombination in
the nanoclusters, and recombination via the interface
states (Fig. 1).
The PL intensity in the samples formed in
nitrogen (in comparison with Ar) ambient is higher due
to passivation of dangling bonds (that are non-radiative
recombination centers) by nitrogen, and also owing to
formation of additional energy states (that act as
radiative recombination centers) at SiO2-Si interfaces.
Table. PL integral intensity values (arb. un.) after the
stages of structure formation.
Forming Low-temperature annealing
conditions
Atmo-
sphere
1100 °C 450 °C
(air)
480 °C
(H2)
450 °C (air) +
480 °C (H2)
Ar 58 523 400 976
N2 103 382 500 509
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 4. P. 352-355.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
354
500 600 700 800 900
100
1000
forming in N2
forming in Ag
P
L
in
te
ns
ity
, a
.u
.
λ, nm
Fig. 2. PL spectra of the samples after the additional low-
temperature annealing (450 °C, 2 h, air).
The PL band with its peak at 560 nm, as a rule, is
attributed to the defects in the SiO2 phase, and it
disappears after a high-temperature annealing. Presence
of this band in the samples annealed in nitrogen is the
evidence of nitrogen interaction with defects, which
increases their thermostability.
An additional annealing of the samples at the
temperature 450 °C in vacuum or argon environment
does not cause noticeable changes in PL spectra. The
substantial changes of spectra are observed after the low-
temperature annealing in the environments of reactive
gases (hydrogen, nitrogen, oxygen) and their mixtures.
The most intensive PL is observed in the samples
formed at 1100 °C in argon, and then subjected to the
additional heat treatment in air at 450 °C and the
following annealing in hydrogen at the temperature
480 °C.
To explain the obtained results, we propose the
model of processes that take place at the combined
annealing of the SiO2-Si structures implanted by silicon.
When annealing in argon, Si clusters are formed, and
numerous dangling bonds at the nanocluster-SiO2
interfaces are created; the low intensity of PL
(comparatively with the structures annealed in nitrogen,
where part of the bonds is passivated) confirms this.
600 700 800 900
10
100
1000
11000C (Ar)
11000C (N2)
11000C (Ar)+4500C
11000C (N2)+4500C
P
L
in
te
ns
ity
, a
.u
.
λ, nm
Fig. 3. PL spectra of the samples after the additional annealing
in hydrogen (480 °C, 2 h).
Confirmation of this is that the additional annealing
in H2 of the samples, formed in Ar, results in PL intensity
growth by ~7 times, while for the samples formed in
nitrogen the PL intensity grows by 5 times only. At the
low-temperature annealing of the samples in air, the
quasichemical reactions take place at nanocluster-matrix
boundaries with participation of oxygen, nitrogen and
silicon. It results in the interface energy states formation,
through which the processes of radiative recombination
occur. In the earlier works devoted to investigations of
SiO2-Si interface, it was shown that annealing at the
temperature 450 °C results in the sharp increase of the
density of electronic states at this interface [17].
More effective formation of radiative centers takes
place when there is a large concentration of dangling
bonds (high-temperature annealing in argon) in
structures. In the case of the forming annealing in
nitrogen ambient, the concentration of these bonds is
less, as a result, the rate of new center formation is less.
The process of electronic state formation at low-
temperature annealing goes until a shell of defect
complexes (containing nitrogen, oxygen and silicon) will
be formed around the silicon nanocrystal. The presence
of dangling bonds before the low-temperature annealing
promotes activation of the autocatalytic for the process
mechanism of radiative center formation [17].
At the same time, formation of radiative centers at
SiO2-Si interfaces is accompanied with creation of new
dangling bonds that are the centers of non-radiative
recombination. It follows from the results on a
subsequent annealing in hydrogen, when dangling bonds
are passivated, and the PL intensity increases, Table.
The much larger growth of the PL intensity is observed
after the treatment in H2 ambient in the samples formed
in argon with the additional low-temperature treatment
(air) in comparison with the samples formed in nitrogen.
It is the evidence that in the samples formed in N2, at the
low-temperature annealing in air, lower concentrations
of complexes with radiative characteristics and dangling
bonds are formed, as the Si nanocluster-SiO2 interfaces
are strongly passivated when formation goes in N2
ambient.
5. Conclusions
The results of experimental researches of photo-
luminescence spectra of the Si nanocluster structures
obtained by implantation of silicon ions to SiO2-Si
structures and high temperature (1100 °C) and following
low-temperature annealings in different environments
are given. It is shown that the PL intensity grows within
the range of implantation doses 2×1016 – 9×1016 cm–2. At
subsequent increase of the dose, there is reduction of the
PL intensity and shift of the PL band peak to the
longwave side.
The additional low-temperature treatments result in
the substantial increase in the PL intensity, thus a
maximum effect is observed after annealing in air. The
spectral position of the PL band changes weakly.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 4. P. 352-355.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
355
Comparison of effect of passivation of non-
radiative recombination centers due to the low-
temperature annealing in the nitrogen or hydrogen
atmosphere has been carried out. It has been shown that
growth of the PL intensity is caused by these two effects:
generation of new centers providing radiative recom-
bination at the nanocrystal-dielectric matrix interfaces,
and passivation of non-radiative recombination centers.
Generation of the new centers of radiative recombination
at low-temperature treatments in air goes more
effectively in the samples formed at the high temperature
annealing in argon ambient, comparatively with
annealing in nitrogen.
Acknowledgements
This work was supported by the MES of Ukraine (Grant
# M/175-2007).
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