Journal of Nanomaterials
Volume 2016 (2016), Article ID 9674741, 7 pages
http://dx.doi.org/10.1155/2016/9674741

Research Article

Influence of Radiation on the Luminescence of Silicon Nanocrystals Embedded into SiO₂ Film

I. P. Lisovskyy,¹ M. V. Voitovych,¹ V. V. Voitovych,² and I. M. Khacevich¹

¹V.Ye. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Prosp. Nauki 41, Kyiv 03028, Ukraine
²Institute of Physics, National Academy of Sciences of Ukraine, Prosp. Nauki 46, Kyiv 03028, Ukraine

Received 14 July 2016; Revised 5 November 2016; Accepted 13 November 2016

Academic Editor: Giuseppe Compagnini

Copyright © 2016 I. P. Lisovskyy et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract.

Influence of γ-irradiation on light emission properties of silicon nanocrystals imbedded into SiO₂ film is investigated. It was shown that small doses of γ-irradiation (10³–10⁵ rad) lead to enhancement of photoluminescence intensity in the nc-Si/SiO₂ samples. This effect was explained by radiation induced passivation of recombination active centers on the nanocrystals surface. High doses of irradiation (~10⁷ rad) lead to the photoluminescence intensity decrease up to 2 times. Radiation treatment of silicon oxide films with embedded amorphous silicon inclusions resulted only in the decrease of the photoluminescence intensity within the whole range of doses (10³–5 × 10⁷ rad). Radiation defects resulting in partial quenching of photoluminescence are characterized with the distributed activation energy of annealing with the peak position at ~0.96 eV and the frequency factor 10⁷ s⁻¹. The nature of such defects and the mechanisms of their creation are discussed.

1. Introduction

It is well known that intensive irradiation of silicon dioxide films in vacuum is capable to form silicon nanocrystals in the result of radiation induced reduction of SiO₂ [1, 2]. This phenomenon and the corresponding mechanisms have been studied in detail. At the same time, study of influence of ionizing radiation on the properties of SiO₂ films with imbedded Si nanocrystals (nc-Si/SiO₂ film structures) was attended much less. On the one hand, Si nanocrystals are predicted to have high radiation hardness [3]. In fact, significant degradation of photoluminescence (PL) of the porous silicon, connected with radiation defects creation, was observed after irradiation by rather high doses (2 × 10⁹–10¹⁰ rad) [4, 5]. Effects of PL intensity enhancement after exposure by lower doses (4.3 × 10⁶−3 × 10⁸ rad) [6] were observed only in the case of irradiation in air atmosphere [5] and were attributed to additional oxidation of porous Si surface under corrosive action of ozone, atomic oxygen, and hydrogen that were formed by illumination. This led to reduction of the concentration of nonradiative recombination centers on the surface of silicon nanocrystals and sometimes to decrease of their size.

On the other hand, one may expect that ionizing irradiation with quanta or particles (X- and γ-rays, electrons) is capable of substantially changing the emitting characteristics of the nc-Si/SiO₂ film structures, taking into account a high radiation sensitivity of the Si–SiO₂ interface. The latter is known results in growth of the fast surface states density, these states being related with silicon to broken bonds [7–9]. In fact, certain enhancement (~1.5 times) of luminescent intensity was observed by us earlier [10] after low dose (~10⁴ rad) ionizing irradiation (γ-ray photons) of SiO₂ films with embedded Si nanocrystals. Contrary to the case of porous silicon, this effect in nc-Si/SiO₂ structures was observed after radiation treatment even in the inert gas or in vacuum; hence, it had another nature. Recently, the authors of [11] reported that proton irradiation (the energy 3.5 MeV and the total fluence 10¹²–10¹⁵ сm⁻²) of nc-Si in SiO₂ multilayers leads to significant decrease of the intensity of luminescence centered near 730 nm, and in appearance of the luminescence band near ~500 nm, assigned to radiative recombination at the radiation induced centers within a-SiO₂ matrix. Larger exposure doses (~10⁶–10⁷ rad), similarly to the case of the porous silicon, led to a partial quenching of PL of the nc-Si/SiO₂ films [10]. Investigation of just this effect to elucidate the nature of the radiation defects created under ionizing exposure of nc-Si/SiO₂ films has been done in the present paper, study of the process of radiation damage annealing being mainly attended.

2. Experimental

SiOx films (x ≈ 1.12) have been produced by thermal evaporation of SiO powder (Cerac Inc., purity of 99.9%) in vacuum (2 × 10⁻³ Пa). SiOx film thickness was measured after the deposition by the microinterferometer MII-4 and amounted to 450 nm. Several SiOx films were implanted with nitrogen ions N⁺ with the energies of 70 and 140 кeV and with the total dose of 8.4 × 10¹⁵ сm⁻² (further nc-Si/SiO₂:N structures). SIMS measurements have confirmed a uniform distribution of the nitrogen in SiOx film with depth.

SiOx films were thermally treated in the argon ambient at 700°C or at 1100°С for 30 min. As it was demonstrated by us earlier [12] using electron diffraction and the high resolution transmission electron microscopy, these thermal treatments resulted in creation of amorphous Si nanoinclusions (na-Si) imbedded into oxide matrix SiOy (y ≈ 1.24) or of crystalline Si nanoinclusions (nc-Si) about 3 nm in size homogeneously distributed within the SiO₂ matrix, correspondingly.

Infrared (IR) transmission spectra were measured using FTIR spectrometer Spectrum BXII PerkinElmer. A silicon substrate (without oxide film) served as the reference sample. The absorption band related to Si–O bonds (maximum position within the range of 1000–1100 сm⁻¹ depending on the oxygen content in the oxide film) was under investigation.

Photoluminescence (PL) spectra were measured at room temperature within the spectral range of 550–1000 nm under the excitation at the 473 nm from the semiconductor laser. The excitation power was about 50 mW. Measured PL spectra were corrected with respect to the spectral sensitivity of measurement setup.

Creation of Si nanocrystals in the nc-Si/SiO₂ and nc-Si/SiO₂:N structures due to high temperature annealing resulted in appearance of rather strong red PL band (peak position in the vicinity of 800 nm, see curve 1 in Figure 1(a)), corresponding value of the energy of light emission (~1.6 eV) being in agreement with that calculated or found experimentally for nc-Si with the size of ~3 nm [13]. PL intensity for the samples doped with nitrogen was by ~3 times larger (see curve 1 in Figure 1(b)), which is also agreed with the data [14]. In the case of na-Si/SiOy samples, PL band was blue shifted (peak position at ~680 nm, see curve 1 in Figure 1(c)) that is in agreement with the known results [15]. The value of corresponding energy (E) enabled us to estimate the size (d) of amorphous Si inclusions, using phenomenological dependence [16]: it was ～3.2 nm.

(a)

(b)

(c)

Figure 1: PL spectra for nc-Si/SiO₂ (a), nc-Si/SiO₂:N (b), and na-Si/SiOy (c) samples. Curves notation: 1, initial samples; 2 and 3, samples irradiated with the doses of 2 × 10⁴ rad and 2 × 10⁷ rad, respectively; 4, sample irradiated (2 × 10⁷ rad) and annealed at T = 300°C.

na-Si/SiOy, nc-Si/SiO₂, and nc-Si/SiO₂:N samples were irradiated with γ-quanta (⁶⁰Со) with the intensity 36.77 rad·s⁻¹ and the energies 1.17 and 1.33 MeV. The dose of exposure varied in the range of 10³ ÷ 5 × 10⁷ rad. The temperature of the samples during γ-irradiation did not exceed 30°С. Irradiation was carried out both in air atmosphere and in vacuum (10⁻³ Torr).

Set of irradiated samples was subjected to isochronous (50 ≤ T ≤ 300°С, 10°С) and isothermal ( min) anneals in argon atmosphere.

3. Results and Discussion

Figure 1 demonstrates influence of radiation on the PL red band for the nc-Si/SiO₂ (a), nc-Si/SiO₂:N (b), and na-Si/SiOy (c) samples. Dose dependences of normalized PL intensity (/, where and are the values of PL intensity for irradiated and initial samples, resp.) for all investigated structures are presented in Figure 2. It is seen that behavior of the samples under irradiation is different depending on the type of structure: the na-Si/SiOy samples are the less sensitive to influence of exposure. Moreover, for Si/SiO₂:N and na-Si/SiOy structures PL intensity monotonically decays with the time of irradiation within the whole range of exposure doses. In contrast to this the dependence of on the exposure dose for the nc-Si/SiO₂ structures is nonmonotonous. In the range of irradiation doses less than ~10⁵ rad the “low dose effect” was observed. This effect consisted in the remarkable (~1.7 times) increase of PL intensity with respect to that for the initial sample. Further irradiation resulted in decrease in the PL intensity, which becomes smaller than the initial one at the irradiation doses above 5 × 10⁵ rad. “Low dose effect” was observed in the nc-Si/SiO₂ samples irradiated both in air atmosphere and in vacuum. This indicates (contrary to the case of porous silicon) the mechanism related to the interaction of γ-quanta with the sample, but not atmosphere influence.

Figure 2: Dose dependence of PL band intensity for nc-Si/SiO₂ (1), nc-Si/SiO₂:N (2), and na-Si/SiOy (3) structures.

The “low dose effect” was explained earlier [10] by passivation of silicon broken bonds on the surface of nc-Si inclusions with hydrogen atoms and hydroxyls, which are released in oxide matrix due to decomposition of SiH and SiOH complexes under irradiation. Data obtained here for the case of irradiation of nc-Si/SiO₂:N structures seem to confirm such a hypothesis. In these structures silicon broken bonds at nc-Si–SiO₂ interface have been partially or completely passivated by nitrogen atoms during the process of sample formation [14, 17, 18], that is why initial PL intensity for nc-Si/SiO₂:N samples was three times higher comparing to ordinary nc-Si/SiO₂ ones. Additional passivation under irradiation of a rather small amount of remaining defects is negligible and does not influence ; thus the irradiation of nc-Si/SiO₂:N systems led to monotonous decrease only (see Figures 1(b) and 2).

High doses of irradiation resulted in essential decay of the PL intensity (see Figures 1 and 2). It was expected and may be connected with creation of radiation defects at nc-Si/SiO₂ interface, which are the centers of nonradiative recombination. Such processes were widely studied earlier in planar Si/SiO₂ systems and, naturally, the general corresponding approaches may be spread for the case of oxide films with embedded silicon nanoinclusions. However, observation of low dose effect in nc-Si/SiO₂ structures enabled us to suppose that there are two competing processes, namely, those leading to enhancement of and those quenching it (formation of nonradiative recombination centers). Low doses of ionizing radiation lead to radiation stimulated passivation of Si dangling bonds at the nc-Si–SО₂ interface, which is more efficient comparing to formation of nonradiative recombination centers. Increase of is observed in result. Passivation can be provided by, for example, the hydrogen atoms and hydroxyls, which are formed in the oxide matrix due to decomposition of SiH and SiOH complexes under the irradiation. Si nanocrystals in nc-Si/SiO₂ systems play a role of the gettering centers, leading to rise in the efficiency of collection on their surfaces of mentioned passivating agent already at the room temperature.

Defect formation leading to decrease of becomes dominating at higher irradiation doses (D > 2 × 10⁴ rad). The equilibrium in both defect formation processes is obtained at the irradiation dose of 2 × 10⁴ rad. At this dose, the concentration of passivated Si broken bonds becomes approximately equal to the concentration of formed nonradiative recombination centers.

Defects formed by irradiation may be eliminated due to low-temperature treatment in vacuum or in inert ambient, resulting in restoration of the PL intensity (see curve 4 in Figure 1(a)). At the same time, IR absorption band connected with stretching vibrations of oxygen atoms in Si-O-Si units (maximum position near ~1090 сm⁻¹) with the shape inherent for SiO₂ phase [19] practically did not vary after irradiation within the whole dose range and low-temperature heat treatments in inert ambient both of the initial and irradiated nc-Si/SiO₂. This fact should mean that irradiation and thermal treatments used in this study did not affect the concentration and structural arrangement of the bridging oxygen atoms in the oxide matrix.

For clarification of the nature of radiation defects, which lead to PL quenching, as well as the mechanism of their formation, detailed study of the thermal annealing processes of radiation induced defects in nc-Si/SiO₂ structures was carried out.

In Figure 3 the results of isochronal annealing (temperature step °С, duration of anneal at every temperature minutes) are presented. It is seen that heat treatment of initial sample did not affect PL intensity within the whole range of temperatures (50–300°С). In the case of irradiated sample, restoration of up to the initial state takes place in the temperature range of 200 ÷ 300°С (Figure 3).

Figure 3: Dependence of the PL intensity on the annealing temperature for initial nc-Si/SiO₂ sample (1) and nc-Si/SiO₂ sample irradiated with the dose of 2 × 10⁷ rad (2).

Isothermal annealing (°С) demonstrated that defect elimination at every temperature is only partial. The temperature determines not only the annealing rate but also the amount of nonannealed portion of the radiation damage. This result is important and means [20] that the radiation defect annealing in nc-Si/SiO₂ structures is characterized by not single activation energy but that distributed in some energy interval.

To determine this activation energy distribution according to [20] a combined heat treatment of one sample was performed, consisting of three successive isothermal annealing cycles at 220, 240, and 280°С. The results are presented in Figure 4. Nonannealed portion of radiation damage was determined as

with , , and being the PL intensity for nonirradiated, irradiated, and annealed samples, respectively.

Figure 4: Curves of isothermal annealing for irradiated nc-Si/SiO₂ sample.

Using the data obtained for the annealing experiments the activation energy and the energy distribution function were calculated from the following expressions [20, 21]:

for the isothermal anneals and

for isochronous annealing, respectively. In expressions (2) to (3), is the thermal treatment time and is the frequency factor, respectively.

Using expressions (2) to (3) for each isothermal annealing cycle (Figure 4), the energy distribution functions were built (Figure 5). The value of A (A = 10³–10¹⁰ s⁻¹) was fitted at the calculations of so as to provide a continuity of distribution between different segments (each of which corresponded to certain isotherm in Figure 4). The best fit corresponded to A = 10⁷ s⁻¹. It can be seen that the calculated distribution function curves based on different experiments (isothermal and isochronous annealing) have a good agreement. The activation energy of annealing of radiation defects that results in a partial decrease in in the nc-Si/SiO₂ structures is distributed in the range of 0.85–1.05 eV with the peak at ~0.96 eV.

Figure 5: Distribution of the activation energy of annealing of radiation damage in nc-Si/SiO₂ structure. Segments were obtained from the results of isothermal annealing. Curve 4 was obtained from the results of isochronous annealing. The value of is 10⁷ s⁻¹. Triangles reflect the results obtained from analysis of isochronal annealing, which is described in the caption of Figure 5.

The values of and were compared to those for the radiation defects both in the single crystal Si bulk and in the planar Si/SiO₂ systems as well as in the near surface oxidized Si layer [20, 22–25]. It is well known that the primary radiation defects in silicon crystals have rather small values of the activation energy of annealing (in the case of vacancies, for example, the value of amounts the meanings of 0.18 and 0.33 eV for n- and p-Si, resp. [25]). The most part of the secondary radiation defects (in particular, agglomerations of the primary defects with impurity atoms) has values much larger (e.g., complexes of vacancies with oxygen atoms) or much less (e.g., complexes of vacancies with donor impurities). Only some secondary radiation defects in silicon crystals may have the values of similar to that calculated in this study. Thus, for example, Si–P6 defect, which includes Si interstitial atoms, is characterized with = 0.92 eV; however it was observed only after neutron irradiation [25]. Vacancy-phosphorous atom complexes (E-centers) have the value of = 0.95 eV [25], but the frequency factor of their annealing process is too high (A = 7 × 10⁸ s⁻¹), and appearance of such defects in the nc-Si/SiO₂ samples seems to be unexpected.

However, the data discussed above are related to the defects which are localized within the bulk of Si crystals. Presence of surface may influence temperature stability of radiation defects. It is known, in particular, that the surface layer (about 2 μm in depth) of oxidized Si single crystals differs from silicon bulk both by larger sensitivity to ionizing radiation and by parameters of radiation damage annealing [26]. Silicon nanocrystals with the diameter of some nanometers embedded into SiO₂ matrix and thus strongly mechanically stressed [27] are more similar to such a surface layer than to silicon bulk. Hence, it seems to be more correct to compare the calculated annealing parameters with those obtained for surface layer of irradiated oxidized silicon crystals. Investigations of the generation life time of the minor carriers in the silicon space charge region under γ-irradiation (with the dose up to 10⁶ rad) made it possible to determine the value of the activation energy of annealing of the corresponding surface radiation defects; it amounted (in the maximum of distribution) the meanings of 1.1–1.2 eV depending on the oxidizing technology regimes [26]. This value also differs from that calculated in the present study.

However, it can be easily shown that in our experiments radiation defects, which have been created in silicon nanocrystals, can not influence their light emitting ability. In fact, it is well known that in Si one γ-quant may form about 10⁻³ сm⁻³ of primary radiation defects [28]. Then the number of the point defects, which have been generated in the bulk of all silicon nanocrystals (with the diameter of ~3 × 10−9 m and the concentration of ~10¹⁸ сm⁻³) after irradiation with the dose of 2 × 10⁷ rad (or ~3.4 × 10¹⁶ γ-quanta), should be about 10¹³ сm⁻³. On the other hand, a decrease in the PL intensity in the nc-Si/SiO₂ structures is known [29] and may be observed if the concentration of the centers of nonradiative recombination amounts the value of 10¹⁶–10¹⁸ сm⁻³. Thus, one can conclude that in the irradiated nc-Si/SiO₂ structures radiation defects, which influence the PL intensity value, are not localized within the bulk of silicon nanocrystals.

Some decades ago the processes of radiation damage creation and elimination in the MOS structures have been studied intensively. In particular, the values of activation energy of annealing both the centers in the oxide and the fast surface states at the Si–SiO₂ interface which were created in the result of different kinds of radiation treatment have been determined [20, 24, 26]. In all the cases activation energy was distributed along the energy axe with the peak position near 0.9 eV, and the meaning of the frequency factor was 10⁷ s⁻¹. These values practically coincide with those calculated in the present work. Hence, one may conclude that the radiation defects, which are formed by γ-irradiation of nc-Si/SiO₂ structures and lead to partial quenching of luminescence, are located, namely, at the nc-Si–SiO₂ interfaces. These defects are the centers of nonradial recombination, their nature and the formation mechanism being identical to those characterizing the radiation surface states in Si/SiO₂ planar systems.

The most probable radiation induced defects at the Si–SiO₂ interface are the silicon broken bonds Si³⁺ [9]. However, some alternative models exist to explain the mechanism of these defects creation due to active treatments (irradiation, hot carriers injection) [9, 30, 31]. Their main mutual feature is that surface states are the secondary defects; the process of radiation damage generation under irradiation takes place in SiO₂ film. In fact, the concentration of the silicon broken bonds, which are created by ionizing radiation within the oxide films at the doses of 10⁶–10⁷ rad, amounts the value of 10¹⁸–10¹⁹ сm⁻³ [32]. This number is not sufficient to influence the Si–O absorption band, but sufficiently large to affect the PL intensity in the case of nc-Si/SiO₂ samples.

4. Conclusions

Gamma irradiation of nc-Si/SiO₂ structures with low (<10⁵ rad) doses both in air and in vacuum resulted in pronounced rise in PL intensity. This effect was explained by radiation assisted passivation of centers of nonradiative recombination at nc-Si–SiO₂ interfaces. “Low dose” effect was absent in the case of na-Si/SiOy and nc-Si/SiO₂:N structures, where irradiation only led to monotonous decrease in the PL intensity.

Larger doses of γ-irradiation of nc-Si/SiO₂ structures resulted in the formation of radiation induced defects that significantly (twice at 10⁷ rad) quench the photoluminescence. These defects are annealed due to heat treatments at the temperatures in the range of 200 ÷ 300°С. The activation energy of annealing is distributed within the energy range of 0.85–1.05 eV with the peak at ~0.96 eV. The frequency factor is 10⁷ s⁻¹. The values of and coincide practically with those determined for the fast surface states formed at the Si–SiO₂ interface by ionizing radiation. This fact allows one to infer the accumulation of radiation induced defects partially quenching the photoluminescence, at the Si nanocrystal/oxide matrix interface. The nature of these defects and the mechanism of their formation are the most likely similar to those pertinent to the surface states formed by ionizing radiation at the planar Si–SiO₂ interfaces.

Competing Interests

The authors declare that they have no competing interests.

References

M. Takeguchi, K. Furuya, and K. Yoshihara, “Structure study of Si nanocrystals formed by electron-induced reduction of SiO₂ at high temperature,” Japanese Journal of Applied Physics, vol. 38, no. 12B, p. 7140, 1999.

X.-W. Du, M. Takeguchi, M. Tanaka, and K. Furuya, “Formation of crystalline Si nanodots in SiO₂ films by electron irradiation,” Applied Physics Letters, vol. 82, no. 7, pp. 1108–1110, 2003.

N. Gerasimenko and Yu. Parkhomenko, Silicon—Nanoelectronics Material, Teknosferra, Moscow, Russia, (Russian) 2007.

E. V. Astrova, V. V. Emtsev, A. A. Lebedev et al., “Degradation of the photoluminesce of the porous silicon under the influence of gamma-radiation ⁶⁰Co,” Fizika i Tekhnika Poluprovodnikov, vol. 29, pp. 1301–1305, 1995 (Russian).

E. V. Astrova, P. Wittmann, V. V. Emtsev et al., “Influence γ-radiation on properties of porous silicon,” Fizika i Tekhnika Poluprovodnikov, vol. 30, pp. 507–514, 1996 (Russian).

J. S. Fu, J. C. Mao, E. Wu et al., “Gamma-rays irradiation: an effective method for improving light emission stability of porous silicon,” Applied Physics Letters, vol. 63, no. 13, pp. 1830–1832, 1993.

C. T. Sah, “Origin of interface states and oxide charges generated by ionizing radiation,” IEEE Transactions on Nuclear Science, vol. 23, no. 6, pp. 1563–1156, 1976.

P. M. Lenahan and P. V. Dressendorfer, “Paramagnetic trivalent silicon centers in gamma irradiated metal-oxide-silicon structures,” Applied Physics Letters, vol. 44, no. 1, pp. 96–98, 1984.

F. J. Grunthaner and P. J. Grunthaner, “Chemical and electronic structure of the SiO₂/Si interface,” Materials Science Reports, vol. 1, no. 2, pp. 65–160, 1986.

I. P. Lisovskyy, I. Z. Indutniĭ, M. V. Muravskaya, V. V. Voitovich, E. G. Gule, and P. E. Shepelyavyĭ, “Enhancement of photoluminescence of structures with nanocrystalline silicon stimulated by low-dose irradiation with γ-ray photons,” Semiconductors, vol. 42, no. 5, pp. 576–579, 2008.

S. Jang, B. S. Joo, S. Kim et al., “Effects of proton irradiation on Si-nanocrystal/SiO₂ multilayers: study of photoluminescence and first-principles calculations,” Journal of Materials Chemistry C, vol. 3, no. 33, pp. 8574–8581, 2015.

A. Szekeres, T. Nikolova, A. Paneva et al., “Silicon nanoparticles in thermally annealed thin silicon monoxide films,” Materials Science and Engineering: B, vol. 124-125, pp. 504–507, 2005.

Y. Kanzawa, T. Kageyama, S. Takeoka, M. Fujii, S. Hayashi, and K. Yamamoto, “Size-dependent near-infrared photoluminescence spectra of Si nanocrystals embedded in SiO₂ matrices,” Solid State Communications, vol. 102, no. 7, pp. 533–537, 1997.

M.-S. Yang, K.-S. Cho, J.-H. Jhe et al., “Effect of nitride passivation on the visible photoluminescence from Si-nanocrystals,” Applied Physics Letters, vol. 85, no. 16, pp. 3408–3410, 2004.

H. Rinnert, M. Vergnat, and A. Burneau, “Evidence of light-emitting amorphous silicon clusters confined in a silicon oxide matrix,” Journal of Applied Physics, vol. 89, no. 1, pp. 237–243, 2001.

H.-S. Kwack, Y. Sun, Y.-H. Cho, N.-M. Park, and S.-J. Park, “Anomalous temperature dependence of optical emission in visible-light-emitting amorphous silicon quantum dots,” Applied Physics Letters, vol. 83, no. 14, pp. 2901–2903, 2003.

A. R. Wilkinson and R. G. Elliman, “The effect of annealing environment on the luminescence of silicon nanocrystals in silica,” Journal of Applied Physics, vol. 96, no. 7, pp. 4018–4020, 2004.

M. López, B. Garrido, C. García et al., “Elucidation of the surface passivation role on the photoluminescence emission yield of silicon nanocrystals embedded in SiO₂,” Applied Physics Letters, vol. 80, no. 9, pp. 1637–1639, 2002.

I. P. Lisovskii, V. G. Litovchenko, V. G. Lozinskii, and G. I. Steblovskii, “IR spectroscopic investigation of SiO₂ film structure,” Thin Solid Films, vol. 213, no. 2, pp. 164–169, 1992.

V. Danchenko, “Characteristics of thermal annealing of radiation damage in MOSFET's,” Journal of Applied Physics, vol. 39, no. 5, pp. 2417–2424, 1968.

W. Primak, “Kinetics of processes distributed in activation energy,” Physical Review, vol. 100, no. 6, pp. 1677–1689, 1955.

V. S. Vavilov, Radiation Effects in Semiconductors and Semiconductor Devices, Atomizdat, Moscow, Russia, 1969.

V. G. Litovchenko, “Nature of radiation effects in layered MIS structures,” Optoelectronics and Semiconductor Technology, vol. 25, pp. 27–35, 1982.

I. P. Lisovskii, V. G. Litovchenko, and R. O. Litvinov, “Effect of UV illumination on the electrical properties of mos layer structures,” Physica Status Solidi (A), vol. 53, no. 1, pp. 253–262, 1979.

V. S. Vavilov, V. F. Кiselyov, and B. N. Мukashev, Defects in Silicon and on Its Surface, Nauka, Moscow, Russia, (Russian) 1990.

V. Y. Kiblik, Investigation of the electro-physical characteristics of the MOS structures exposed to radiation treatments [Ph.D. thesis], 1982.

B.-H. Kim, M. A. Pamungkas, M. Park, G. Kim, K.-R. Lee, and Y.-C. Chung, “Stress evolution during the oxidation of silicon nanowires in the sub-10 nm diameter regime,” Applied Physics Letters, vol. 99, no. 14, Article ID 143115, 3 pages, 2011.

V. M. Кulakov, V. I. Shakhovtsov, and S. I. Shakhovtsova, Comparative Efficiency of the Action of the Nuclear Radiation on the Semiconductor Materials, Naukova Dumka, Kyiv, Ukraine, 1978 (Russian).

K. Sato and K. Hirakuri, “Influence of paramagnetic defects on multicolored luminescence from nanocrystalline silicon,” Journal of Applied Physics, vol. 100, no. 11, pp. 114303–114306, 2006.

V. G. Litovchenko, I. P. Lisovskii, and R. O. Litvinov, “Application of UV light for studying surface reactions in layer structures,” Applications of Surface Science, vol. 6, no. 1, pp. 15–28, 1980.

D. M. Fleetwood, S. T. Pantelides, and R. D. Schrimps, Defects in Microelectronic Materials and Devices, Taylor & Francis Group, LLC, Boca Raton, Fla, USA, 2008.

A. N. Vologdin and A. P. Lysenko, Radiation Effects in Integral Circuits and the Test Methods of Radiation Resistance of Semiconductor Electronics Products, МGIAM, Мoscow, Russia, 2002 (Russian).