Effect of the desorption process on photoluminescence excitation spectra of porous silicon
Photoluminescence (PL), photoluminescence excitation (PLE) and FTIR methods were used to study the PL excitation mechanism in porous silicon (PS). Two types of PLE spectra were observed, consisting of two (visible and ultraviolet) and one (only ultraviolet) bands. The intensities of each PLE band de...
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Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
1998
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| Назва видання: | Semiconductor Physics Quantum Electronics & Optoelectronics |
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| Цитувати: | Effect of the desorption process on photoluminescence excitation spectra of porous silicon / T.V. Torchinskaya, N.E. Korsunskaya, L.Yu. Khomenkova, B.R. Dzhumaev, A. Many, Y. Goldstein, E. Savir // Semiconductor Physics Quantum Electronics & Optoelectronics. — 1998. — Т. 1, № 1. — С. 61-65. — Бібліогр.: 4 назв. — англ. |
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irk-123456789-1146712017-03-12T03:02:24Z Effect of the desorption process on photoluminescence excitation spectra of porous silicon Torchinskaya, T.V. Korsunskaya, N.E. Khomenkova, L.Yu. Dzhumaev, B.R. Many, A. Goldstein, Y. Savir, E. Photoluminescence (PL), photoluminescence excitation (PLE) and FTIR methods were used to study the PL excitation mechanism in porous silicon (PS). Two types of PLE spectra were observed, consisting of two (visible and ultraviolet) and one (only ultraviolet) bands. The intensities of each PLE band depend differently on the anodization conditions during aging and thermal treatment. Two excitation channels were shown to exist in PS. The visible PLE band at 300 K was attributed to light absorption of some species on the surface of Si wires. Досліджено механізм збудження фотолюмінесценції пористого кремміго методами фотолюмінесценції та інфрачервоного поглинання. Показано, що існує два типі спектрів збудження, які містять або дві смуги (видиму та ультрафіолетову), або тільки одну (ультрафіолетову) смугу. Вивчено залежності інтенсивностей кожної смуги від режимів електрохімічного травлення, а також їх поведінка у процесі старіння та термічного оброблення пористих шарів. Показано, що існують два канали збудження фотолюмінесценції. Видима смуга у спектрі збудження при 300 К пов.язується з поглинанням світла у речовинах, які адсорбовані на поверхні кремнієвих ниток. Исследован механизм возбуждении фотолюминесценции пористого кремнии методами фотолюминесценции и инфракрасного поглощения. Показано, что существуют два типа спектров возбуждения, которые содержат либо две полосы (видимую и ультрафиолетовую), либо только одну (ультрафиолетовую) полосу. Изучены зависимости ингенсивностей каждой полосы возбуждения от режимов электрохимического травления, а также их поведение в процессе старения и термических обработок пористых слоев. Показано, что существуют два канала возбуждения фотолюминесценции. Видимая полоса в спектре возбуждения при 300 К связывается с поглощением света веществами, адсорбированными на поверхности кремниевых нитей. 1998 Article Effect of the desorption process on photoluminescence excitation spectra of porous silicon / T.V. Torchinskaya, N.E. Korsunskaya, L.Yu. Khomenkova, B.R. Dzhumaev, A. Many, Y. Goldstein, E. Savir // Semiconductor Physics Quantum Electronics & Optoelectronics. — 1998. — Т. 1, № 1. — С. 61-65. — Бібліогр.: 4 назв. — англ. 1560-8034 PACS 78.55.H http://dspace.nbuv.gov.ua/handle/123456789/114671 en Semiconductor Physics Quantum Electronics & Optoelectronics Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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English |
| description |
Photoluminescence (PL), photoluminescence excitation (PLE) and FTIR methods were used to study the PL excitation mechanism in porous silicon (PS). Two types of PLE spectra were observed, consisting of two (visible and ultraviolet) and one (only ultraviolet) bands. The intensities of each PLE band depend differently on the anodization conditions during aging and thermal treatment. Two excitation channels were shown to exist in PS. The visible PLE band at 300 K was attributed to light absorption of some species on the surface of Si wires. |
| format |
Article |
| author |
Torchinskaya, T.V. Korsunskaya, N.E. Khomenkova, L.Yu. Dzhumaev, B.R. Many, A. Goldstein, Y. Savir, E. |
| spellingShingle |
Torchinskaya, T.V. Korsunskaya, N.E. Khomenkova, L.Yu. Dzhumaev, B.R. Many, A. Goldstein, Y. Savir, E. Effect of the desorption process on photoluminescence excitation spectra of porous silicon Semiconductor Physics Quantum Electronics & Optoelectronics |
| author_facet |
Torchinskaya, T.V. Korsunskaya, N.E. Khomenkova, L.Yu. Dzhumaev, B.R. Many, A. Goldstein, Y. Savir, E. |
| author_sort |
Torchinskaya, T.V. |
| title |
Effect of the desorption process on photoluminescence excitation spectra of porous silicon |
| title_short |
Effect of the desorption process on photoluminescence excitation spectra of porous silicon |
| title_full |
Effect of the desorption process on photoluminescence excitation spectra of porous silicon |
| title_fullStr |
Effect of the desorption process on photoluminescence excitation spectra of porous silicon |
| title_full_unstemmed |
Effect of the desorption process on photoluminescence excitation spectra of porous silicon |
| title_sort |
effect of the desorption process on photoluminescence excitation spectra of porous silicon |
| publisher |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| publishDate |
1998 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/114671 |
| citation_txt |
Effect of the desorption process on photoluminescence excitation spectra of porous silicon / T.V. Torchinskaya, N.E. Korsunskaya, L.Yu. Khomenkova, B.R. Dzhumaev, A. Many, Y. Goldstein, E. Savir // Semiconductor Physics Quantum Electronics & Optoelectronics. — 1998. — Т. 1, № 1. — С. 61-65. — Бібліогр.: 4 назв. — англ. |
| series |
Semiconductor Physics Quantum Electronics & Optoelectronics |
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2025-07-08T07:47:28Z |
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| fulltext |
61© 1998 ²íñòèòóò ô³çèêè íàï³âïðîâ³äíèê³â ÍÀÍ Óêðà¿íè
Ô³çèêà íàï³âïðîâ³äíèê³â, êâàíòîâà òà îïòîåëåêòðîí³êà. 1998. Ò. 1, ¹ 1. Ñ. 61-65.
Semiconductor Physics, Quantum Electronics & Optoelectronics. 1998. V. 1, N 1. P. 61-65.
PACS 78.55.H
Effect of the desorption process on photoluminescence
excitation spectra of porous silicon
T. V. Torchinskaya, N. E. Korsunskaya, L. Yu. Khomenkova, B. R. Dzhumaev
Institute of Semiconductor Physics, NAS Ukraine, 45 prospekt Nauki, Kyiv, 252028, Ukraine
A. Many, Y. Goldstein, E. Savir
Racah Institute of Physics, The Hebrew University, Jerusalem, ISRAEL
Abstract. Photoluminescence (PL), photoluminescence excitation (PLE) and FTIR methods were used
to study the PL excitation mechanism in porous silicon (PS). Two types of PLE spectra were observed,
consisting of two (visible and ultraviolet) and one (only ultraviolet) bands. The intensities of each PLE
band depend differently on the anodization conditions during aging and thermal treatment. Two excita-
tion channels were shown to exist in PS. The visible PLE band at 300 K was attributed to light absorp-
tion of some species on the surface of Si wires.
Keywords: Photoluminescence; excitation; porous silicon; desorbtion.
Paper received 16.07.98; revised manuscript received 02.09.98; accepted for publication 27.10.98.
1. Introduction
In spite of a large body of research made on the photolumi-
nescence (PL) of porous silicon (PS), the origin of visible
light emission (silicon wires or substances on their surface)
and the mechanism of its excitation are still unknown.
In this paper, PL and PL excitation (PLE) measurements
and FTIR methods were employed to study the mechanism
of PL excitation in porous silicon. To elucidate the role of
surface substances in the photoluminescence of porous sili-
con, three approaches were used, involving studies of: (i)
the dependences of the PL and PLE spectra on the
anodization conditions; (ii) the effect of thermal and ultra-
sound treatment on the PL, PLE and FTIR spectra, and (iii)
aging phenomena in air and vacuum by the techniques of
PL and, especially, PLE.
It should be noted that up to now, dependences of the
PLE spectra on the conditions of preparation and aging have
not been studied systematically.
2. Experimental results and discussion
Porous silicon samples were prepared from p-type B-doped,
(100) oriented silicon wafers with the resistivity of 4.5 Ω⋅cm
by anodization in the solution of HF:H
2
O:C
2
H
5
OH = 1:1:2.
The current density (I
a
) and time (t
a
) of anodization were
25, 50, 100, 200 mA/cm2 and 2, 8, 15 min respectively. Pho-
toluminescence was excited with the light of a Xe lamp
passed through the MDR-23 monochromator. XPS meas-
urements were performed with the LAS 2000 (RIBER)
spectrometer in the energy range of 0 to 1000 eV.
The photoluminescence (PL) and photoluminescence
excitation (PLE) spectra are shown in fig.1 and fig. 2 re-
spectively. The PLE spectrum consists of two overlapping
bands represented by a broad maximum in the visible spec-
tral range (380�450 nm) (V band) and a steep rise (or maxi-
mum) in the ultraviolet range (UV band).
It is essential that positions of the PL peaks depend on
the wavelength of the excitation light. Namely, the peak of
the photoluminescence excited by the light from the UV band
(W
UV
) is located at shorter wavelengths than that of PL ex-
cited by the light from the V band (W
V
) (fig. 1(c)).
2.1. Dependence of PL and PLE spectra on
anodization conditions
An increase in the anodization current density results in a
shift of PL towards shorter wavelengths and in a decrease of
the PL intensity and its full width at half maximum (FWHM)
independently of the excitation light wavelength (fig. 1(a)).
The latter effect takes place mainly in the case of the UV
excitation. At the same time, the intensity of the V band in
the PLE spectrum decreases, and at the density of anodization
current I
a
= 200 mA/cm2 this band eventually disappears
(fig. 2(a)). Comparison of the curves shown in fig. 2 makes
it possible to estimate the overlapping range of the V and
UV excitation bands. This range covers the range from 350
to 450 nm at least.
Longer anodization times lead to a shift of the PL peak
toward longer wavelengths and a rise of the PL intensity
and its FWHM (fig. 1(b)). The intensity of the V band in the
PLE spectrum also increases (fig. 2(b)). These data indicate
T. V. Torchinskaya et al.: Effect of desorption on photoluminescence excitation...
62 ÔÊÎ, 1(1), 1998
SQO, 1(1), 1998
a non-elementary nature of the PL band. The V excitation
band corresponds to the PL component with longer wave-
lengths than that corresponding to the UV excitation, since
an increase (decrease) in the V band intensity in PLE spec-
trum leads to a shift of the PL peak towards longer (shorter)
wavelengths.
2.2. Effect of the aging processes at the air, in a
liquid, and in vacuum on the PL and PLE spectra
The investigation of the PS aging process at the air has shown
that its kinetics is different for the various light wavelength
excitation and may be non-monotone. The PL intensity ex-
cited by light wavelength from the V band (λ = 480 nm),
when the contribution in the UV excitation band is negligi-
ble (fig. 3, curve 1), drops monotonical with time. The in-
600 700 800
0
50
100
150
200
b
a
W
,
a
rb
.u
n
.
25 mA/cm2
15 min
8 min
2 min
λ, nm
500 600 700 800
0
50
100
150
200
8 min
100
50
25 mA/cm2
600 700 800
0
50
100
150
200
c
λ = 337 nm
λ = 480 nm
Fig. 1. PL spectra of as-prepared PS samples for different preparation conditions at the excitation wavelength 337 nm (a, b) and for
different excitation wavelengths (c).
350 400 450 500
0
50
100
150
200
250
8 min
x5W
, a
rb
.u
n.
λ, nm
I=200mA/cm 2
I=100mA/cm 2
I=25 mA/cm 2
350 400 450 500 550
0
50
100
150
200
250
300
2 min
15 min
8 min
I=25 mA/cm 2
Fig. 2. PLE spectra measured at the lu-
minescence peak energy for PS sam-
ples prepared under various conditions.
tensity of PL excited by the light wavelength from the UV
band (λ = 330 nm) first decreases insignificantly and then
rises (fig. 3, curve 2). When the PLE spectrum contains only
the UV band, only an increase in the PL intensity is ob-
served. Thus, during the process of aging, the V band in the
PLE spectra decreases, and the UV band increases. So, there
are two processes that take place during the aging. At the
same time, the non-monotony of the curve 2 in fig. 3(a) is
obviously due to their competition.
Different behavior of the V and UV bands in PLE spec-
tra with respect to the anodization conditions and aging in-
dicates the existence of two independent channels of PL
excitation corresponding to these bands.
It is essential that a reduction of the excitation efficiency
in the V band at the initial stage (fig. 3) is accompanied by a
shift of the peak of the PL excited by the light from the UV
and V bands towards shorter wavelengths (fig. 4). In addi-
T. V. Torchinskaya et al.: Effect of desorption on photoluminescence excitation...
63ÔÊÎ, 1(1), 1998
SQO, 1(1), 1998
tion, its FWHM decreases due to the prevalent drop of the
long-wavelength component (fig. 4(a), curves 3 and 4).
To clarify the nature of the processes manifested by the
transformations of the PL and PLE spectra during aging,
we studied the effect of keeping of as-prepared porous Si
samples in vacuum and in liquid (specifically, in water and
in aqueous NaCl solution). The latter is often employed for
electroluminescence studies. Keeping in vacuum was found
to result only in a reduction of the PL intensity (fig. 5). In
addition, the V band intensity in the PLE spectrum decreases
(fig. 5(b), curve 2), while the shape of the PL band changes
in the same way as during aging in the air. It is essential that
the short-wavelength edges of the PL bands before and after
keeping in vacuum coincide. This fact means that a drop of
the PL intensity is associated not with an increase in the
concentration of the nonradiative recombination centers, but
with a reduction of the long-wavelength component. A simi-
lar behavior of PL is observed when keeping PS samples in
NaCl solution (fig. 6).
To separate this component, let us analyze the data shown
in fig. 5(a). The positions of W
UV
and W
V
peaks for as-pre-
pared PS samples are different, but after keeping in vacuum
they coincide. So, in these conditions the contribution of the
long-wavelength component seems to be negligible. For this
reason, the suppressed component can be separated by sub-
tracting curve 2 from curve 1. The result of this procedure is
shown in fig. 5(a) (curve 5).
A similar behavior of the PL and PLE spectra at the ini-
tial stage of aging in the air and when keeping in vacuum
leads us to the conclusion that the reduction of the PL inten-
sity (its long-wavelength component) is caused by desorption
of some substance from the surface of Si wires. Thus, one of
the PL excitation channels is associated with a substance
absorbed on the surface of Si wires (so-called surface exci-
tation). Because of the overlapping of the excitation bands
associated with two channels, the spectrum of the PL ex-
cited by the light from both the V band and the UV band
may contain the long-wavelength component. Obviously, this
may be the reason for the shift of the W
V
and W
UV
peaks
after the treatments mentioned above.
350 400 450 500 550
0
50
100
b
2
1
Wavelength , nm
W
P
LE
,
a
rb
.u
n.
550 600 650 700 750 800 850
0
50
100
150
a
W
P
L ,
a
rb
.u
n.
Wavelength , nm
4
3
2
1
Fig. 3. Variation of the PL intensity caused by aging of PS sam-
ples: 1 � 480 nm; 2 � λ
exc
= 330 nm.
Fig. 4. Transformations of the PL and PLE spectra caused by aging in the air at 300 K: a) PL spectra at λ
exc
= 337 (1, 2) and 480 (3, 4)
nm of as-prepared (1, 3) and aged (2, 4) PS samples; curve 5 obtained by subtracting curve 2 from curve 1; b) PLE spectra of as-prepared
(1) and aged for 7 days (2) PS samples.
T. V. Torchinskaya et al.: Effect of desorption on photoluminescence excitation...
64 ÔÊÎ, 1(1), 1998
SQO, 1(1), 1998
The infrared absorption spectrum of as-prepared PS ex-
hibits a number of features which can be ascribed to the
Si-H (800�900 cm-1, 2090�2140 cm-1), Si-O (1050�
�1170 cm-1), O-Si-H (2200�2240 cm-1), C-H (2850�
�2930 cm-1), and O-H (1620 cm-1, 3300�3600 cm-1) bonds
(Fig. 7). The presence of the C-H related band is evidently
caused by a component contained in the electrolyte � namely,
ethanol. Fig. 7 (curve 2) shows the FTIR spectra of a PS
sample after thermal treatment at 370 K for 1 h. It is seen
that the intensity of bands attributed to the O-H and C-H
bonds decreases. At the same time, the Si-H, Si-O and O-Si-
H related bands change insignificantly.
Therefore, the surface channel of PL excitation may be
associated with ethanol or water. This conclusion is in agree-
ment with the data on the effect of pumping-out and water
vapor treatment on the PL intensity [1].
It is known that water molecules do not have a light ab-
sorption band in the visible range of 350�450 nm. How-
ever, water molecule complexes containing some impuri-
ties (Li, Na, K, H, CH
3
, etc.) do exhibit a photolumines-
cence in the 350�500 nm range [2]. Thus, we can conclude
that visible PL excitation may be caused by water complexes
with some impurities, for example, H, CH
3
and, possibly, F
and B.
It should be noted that PL excitation in PS is usually
attributed to light absorption in Si wires [3]. This conclu-
sion is often based on analysis of PLE spectra similar to
those shown in fig. 2(a) for PS samples prepared at
100 mA/cm2, and on the assumption that in the limit of the
optically thin sample the PLE signal is proportional to the
absorption, provided that the quantum efficiency is inde-
pendent of the exciting photon energy. From these spectra,
the dependence of α(hν) was determined. It was attributed
to two indirect light absorption transitions in Si. The shift of
the absorption edge to higher energies in comparison to that
in the bulk silicon was ascribed to the effect of quantum
confinement [4]. Thus, the UV channel may be due to the
absorption in Si wires, while, apparently, one cannot exclude
the contribution of light absorption by suboxides on the sur-
face of Si wires (see below).
We applied the analysis described above to both types
of PLE spectra of our PS samples (fig. 2(a)). The PLE sig-
nal detected near the luminescence peak energy is shown in
fig. 8 as a function of the excitation energy. For low excita-
tion energies, the signal in the PLE spectra of the first type
(fig. 8, curve 1) follows the dependence (α
PLE
hν)1/2 ~
550 600 650 700 750 800 850
0
50
100
150
a
5
4
3
2
1
W
P
L,
ar
b.
un
.
Wavelength , nm
350 400 450 500 550
0
50
100
b
2
1
Wavelength , nm
W
P
L
E
,
a
rb
.u
n
.
Fig. 5. Transformations of PL and PLE spectra caused by aging in vacuum at 300 K: a) PL spectra at l
exc
= 330 (1, 2) and 480 (3, 4) nm
of as-prepared (1, 3) and aged (2, 4) PS samples; b) PLE spectra of as-prepared PS samples (1) and those kept in vacuum (2).
600 700 800 900
0
10
20
30
40
50
60
2
1
W
, a
rb
.u
n.
λ, nm
Fig. 6. PL spectra of as-prepared PS samples (1) and those kept in
NaCl solution (2).
T. V. Torchinskaya et al.: Effect of desorption on photoluminescence excitation...
65ÔÊÎ, 1(1), 1998
SQO, 1(1), 1998
3000 2000 1000
1
2
2
1
Si-O
Si-H
Si-HC-HO-H
Wavenumber, cm-1
A
bs
or
ba
nc
e,
a
rb
. u
n.
Fig. 7. FTIR spectra of PS samples: as-prepared (1) and thermally
treated at 370 K for 1 h (2).
Fig. 8. The dependence of the PLE signal on the excitation photon
energy for two PS samples prepared at current densities I
a
= 25 (1)
and 100 (2) mA/cm2 for the same time t = 8 min.
~ (hν-E
e
) with two different slopes and two cut-offs at E
e1
=
= 1.9, 2.2 eV and E
e2
= 2.4, 2.7 eV. At the same time, for
low excitation energies, the signal in the PLE spectra of the
second type (fig. 8, curve 2) is also described by the same
kind of dependence (cut-off at E
e1
= 1.9, 2.2 eV). So, for
both cases, the light absorption dependences correspond to
indirect transitions.
We should conclude that the light absorption of some
species on the surface of Si wires is also characterized by
the dependence (α
PLE
hν)1/2 ~ hν. This dependence agrees
with the assumption that these species are complexes (or
clusters). Thus, the dependence (α
PLE
hν)1/2 ~ (hν � E
e1
) and
the absorption edge at E
e1
= 1.9, 2.2 eV can be due to light
absorption not only in Si wires, but also in some complexes
on their surface. So, this kind of light absorption behavior
cannot be considered as an evidence of absorption in Si
wires.
3. Conclusions
There are two types of PLE spectra in porous silicon con-
taining two (visible and ultraviolet) or one (only ultraviolet)
bands. We have shown that the visible PLE band at 300 K is
associated with some complexes (water molecules with im-
purities) on the surfaces of Si wires.
This work was supported by the Ministry of Science and
Technology of Ukraine and the Ministry of Sciences of Is-
rael (grant 2M/1406).
References
1. M. S. Brodin, V. N. Bykov, D. B. Dan'ko, Ukr. Fiz. Zhurn., 40, p. 933
(1995).
2. J. Stauff, J. Chem. Physik 74(1970)358.
3. L. Wang, M. T. Wilson, N. M. Haegel, Appl. Phys. Lett. 62(1993)1113.
4. M. Ben-chorin, B. Averbukh, D. Kovalev, G. Polisski, F. Koch, Phys.
Rev. Lett. 77(1996)763 .
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*Ðàêàõ ²íñòèòóò ô³çèêè, Õåáðþ Óí³âåðñèòåò, ²çðà¿ëü
Ðåçþìå. Äîñë³äæåíî ìåõàí³çì çáóäæåííÿ ôîòîëþì³íåñöåíö³¿ ïîðèñòîãî êðåìì³ãî ìåòîäàìè ôîòîëþì³íåñöåíö³¿ òà
³íôðà÷åðâîíîãî ïîãëèíàííÿ. Ïîêàçàíî, ùî ³ñíóº äâà òèï³ ñïåêòð³â çáóäæåííÿ, ÿê³ ì³ñòÿòü àáî äâ³ ñìóãè (âèäèìó òà
óëüòðàô³îëåòîâó), àáî ò³ëüêè îäíó (óëüòðàô³îëåòîâó) ñìóãó. Âèâ÷åíî çàëåæíîñò³ ³íòåíñèâíîñòåé êîæíî¿ ñìóãè â³ä ðåæèì³â
åëåêòðîõ³ì³÷íîãî òðàâëåííÿ, à òàêîæ ¿õ ïîâåä³íêà ó ïðîöåñ³ ñòàð³ííÿ òà òåðì³÷íîãî îáðîáëåííÿ ïîðèñòèõ øàð³â. Ïîêàçàíî, ùî
³ñíóþòü äâà êàíàëè çáóäæåííÿ ôîòîëþì³íåñöåíö³¿. Âèäèìà ñìóãà ó ñïåêòð³ çáóäæåííÿ ïðè 300 Ê ïîâ�ÿçóºòüñÿ ç ïîãëèíàííÿì
ñâ³òëà ó ðå÷îâèíàõ, ÿê³ àäñîðáîâàí³ íà ïîâåðõí³ êðåìí³ºâèõ íèòîê.
ÂËÈßÍÈÅ ÏÐÎÖÅÑÑÀ ÄÅÑÎÐÁÖÈÈ ÍÀ ÑÏÅÊÒÐÛ ÂÎÇÁÓÆÄÅÍÈß ÔÎÒÎËÞÌÈÍÅÑÖÅÍÖÈÈ
ÏÎÐÈÑÒÎÃÎ ÊÐÅÌÍÈß
Ò. Â. Òîð÷èíñêàÿ, Í. Å. Êîðñóíñêàÿ, Ë. Þ. Õîìåíêîâà, Á. Ð. Äæóìàåâ, À. Ìýíè*, Þ. Ãîëäñòåéí*, Ý. Ñàâèð*
Èíñòèòóò ôèçèêè ïîëóïðîâîäíèêîâ ÍÀÍ Óêðàèíû
*Ðàêàõ Èíñòèòóò ôèçèêè, Õåáðþ Óíèâåðñèòåò, Èçðàèëü
Ðåçþìå. Èññëåäîâàí ìåõàíèçì âîçáóæäåíèè ôîòîëþìèíåñöåíöèè ïîðèñòîãî êðåìíèè ìåòîäàìè ôîòîëþìèíåñöåíöèè è
èíôðàêðàñíîãî ïîãëîùåíèÿ. Ïîêàçàíî, ÷òî ñóùåñòâóþò äâà òèïà ñïåêòðîâ âîçáóæäåíèÿ, êîòîðûå ñîäåðæàò ëèáî äâå ïîëîñû
(âèäèìóþ è óëüòðàôèîëåòîâóþ), ëèáî òîëüêî îäíó (óëüòðàôèîëåòîâóþ) ïîëîñó. Èçó÷åíû çàâèñèìîñòè èíãåíñèâíîñòåé êàæäîé
ïîëîñû âîçáóæäåíèÿ îò ðåæèìîâ ýëåêòðîõèìè÷åñêîãî òðàâëåíèÿ, à òàêæå èõ ïîâåäåíèå â ïðîöåññå ñòàðåíèÿ è òåðìè÷åñêèõ
îáðàáîòîê ïîðèñòûõ ñëîåâ. Ïîêàçàíî, ÷òî ñóùåñòâóþò äâà êàíàëà âîçáóæäåíèÿ ôîòîëþìèíåñöåíöèè. Âèäèìàÿ ïîëîñà â ñïåêòðå
âîçáóæäåíèÿ ïðè 300 Ê ñâÿçûâàåòñÿ ñ ïîãëîùåíèåì ñâåòà âåùåñòâàìè, àäñîðáèðîâàííûìè íà ïîâåðõíîñòè êðåìíèåâûõ íèòåé.
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