Improved model of optical phonon confinement in silicon nanocrystals

Володин, В. А.; Sachkov, V. A.

doi:10.1134/s1063776112130183

Cited by 75 publications

(36 citation statements)

References 27 publications

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“…Data on the crystallite size depending on the full width at half maximum of the TO peak assuming a spherical shape of nanocrystallites are given in ref. 29. Figure 7 shows the crystallite size in the film after annealing versus synthesis temperature of the a-Si film.…”

Section: Resultsmentioning

confidence: 98%

Solid-phase crystallization of high growth rate amorphous silicon films deposited by gas-jet electron beam plasma CVD method

et al. 2014

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Solid phase crystallization of amorphous silicon films (a-Si:H) deposited by gas-jet electron beam plasma chemical vapor deposition method and annealed at 700°C in vacuum has been investigated. This method provides high deposition rates (up to 2.3 nm/s) of a-Si:H thin films in a standard vacuum chamber. The effects of varying the substrate temperature from 190 to 415°C on the structural and optical properties of the as-deposited amorphous films and postannealed nanocrystalline films have been investigated. The crystallite size was determined by X-ray diffraction (about 5-8 nm) and agrees with that obtained from Raman scattering. The estimated degree of crystallinity was 45%-59%. Optical transmission spectra were recorded to investigate the optical properties and thickness of the silicon thin films. The refractive index and optical band gap data was obtained for both as-deposited amorphous and post-annealed nanocrystalline silicon. The behavior of the refractive index of nanocrystalline silicon depending on the substrate temperature is correlated with the crystalline volume fraction. a-Si:H films obtained at low temperatures have larger crystallite size and better crystallinity after annealing.Résumé : Nous étudions la cristallisation en phase solide de films de silicium amorphe (a-Si:H) fabriqués par dépôt chimique en phase vapeur avec faisceau de plasma et jet électronique, avant un recuit à 700°C, le tout dans le vide. Cette méthode donne un fort taux de déposition (jusqu'à 2.3 nm/s) de a-Si:H dans une chambre à vide standard. Nous étudions l'effet de varier la température du substrat de 190 à 415°C sur les propriétés structurelles et optiques des films tels que déposés avant recuit et des films nano-cristallisés après recuit. Nous déterminons la grosseur des cristallites par XRD (environ 5-8 nm) et elle correspond aux résultats par diffusion Raman. La cristallinité varie entre 45 % et 59 %. Nous enregistrons les spectres de transmission optique pour étudier les propriétés optiques et l'épaisseur des films de Si. Nous obtenons l'indice de réfraction et les données sur la bande interdite optique des films tels que déposés et après recuit. La dépendance sur la température du substrat de l'indice de réfraction est corrélée avec la fraction cristalline en volume. Les films de a-Si:H obtenus à basse température ont des cristallites plus grosses et une meilleure cristallinité après recuit. [Traduit par la Rédaction]

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Section: Resultsmentioning

confidence: 98%

Solid-phase crystallization of high growth rate amorphous silicon films deposited by gas-jet electron beam plasma CVD method

et al. 2014

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“…After the femtosecond pulse laser annealing one can see the growth of amorphous peaks and also the appearance of a nanocrystalline peak -the narrow line about 519-520 cm -1 indicating the presence of Si nanocrystals. According to phonon confinement model [9], the average size of the Si nanocrystals that we found here is about 10 nm. It is concerned by HRTEM data ( fig.…”

Section: Femtosecond Pulse Laser Treatments Of Sio X Filmsmentioning

confidence: 97%

“…Due to scattering at optical phonon modes localized in the nanocrystals, the Raman spectrum of nanocrystals is characterized by relatively narrow peak at a position of 500-520 cm -1 . The position and the width of the peak strongly depend on size and structure of the nanocrystals according to dispersion of the localized optical phonons [9]. Figure 4 shows the Raman spectra of as-deposited SiO x :H films with absence of additional silicon (x~2, sample 4-0) and highest content of additional (silicon (x~1.6, sample 1-0).…”

Section: Study Of As-deposited Structures and Structures After Furnacmentioning

confidence: 98%

Formation of Si nanocrystals in SiO_x, SiO_x:C:H films and Si/SiO₂multilayer nano-heterostructures by pulse laser treatments

et al. 2014

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Furnace annealing and pulse laser treatments, including nanosecond laser treatments (KrF laser 248 nm wavelength, 20 ns pulse duration and XeCl laser 308 nm wavelength, 10 ns pulse duration) and femtosecond laser treatments (Tisapphire laser, 800 nm wavelength, <30 fs pulse duration) were applied for crystallization of amorphous hydrogenated silicon films, SiO x films and multilayer nanostructures. The as-deposited and annealed structures were studied using optical methods and electron microscopy techniques. The influence of impurities on crystallization and formation of Si nanoclusters was studied. Regimes for pulse laser crystallization of amorphous Si nanoclusters and nanolayers were found. The developed approach can be used for the creation of dielectric films with semiconductor nanoclusters on nonrefractory substrates.

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“…PCM allows us to calculate the Raman spectra for NCs of various sizes [12][13][14]. The physical entity of the model is the following.…”

Section: Raman Scattering In Sio X and Sin X Films: Phonon Confinemenmentioning

confidence: 99%

Silicon Nanocrystals and Amorphous Nanoclusters in SiO_x and SiN_x: Atomic, Electronic Structure, and Memristor Effects

Володин¹,

Gritsenko²,

Gismatulin³

et al. 2020

Nanocrystalline Materials

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Semiconductor nanocrystals in dielectric films are interesting from fundamental aspect, because quantum-size effects in them appear even at room temperature, so such objects can be called as "quantum dots". Silicon nanocrystals and amorphous silicon nanoclusters in substoichiometric SiO x and SiN x films are traps for electrons and holes that apply in nonvolatile memory devices. In this chapter the formation of silicon nanocrystals and silicon amorphous nanoclusters in SiO x and SiN x films was studied using structural and optical methods. The phonon confinement model was refined to obtain sizes of silicon nanocrystals from analysis of Raman scattering data. Structural models that lead to nanoscale potential fluctuation in amorphous SiO x and SiN x are considered. A new structural model which is intermediate between random mixture and random bonding models is proposed. Memristor effects in SiO x films are discussed.

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Improved model of optical phonon confinement in silicon nanocrystals

Cited by 75 publications

References 27 publications

Solid-phase crystallization of high growth rate amorphous silicon films deposited by gas-jet electron beam plasma CVD method

Solid-phase crystallization of high growth rate amorphous silicon films deposited by gas-jet electron beam plasma CVD method

Formation of Si nanocrystals in SiO_x, SiO_x:C:H films and Si/SiO₂multilayer nano-heterostructures by pulse laser treatments

Silicon Nanocrystals and Amorphous Nanoclusters in SiO_x and SiN_x: Atomic, Electronic Structure, and Memristor Effects

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Improved model of optical phonon confinement in silicon nanocrystals

Cited by 75 publications

References 27 publications

Solid-phase crystallization of high growth rate amorphous silicon films deposited by gas-jet electron beam plasma CVD method

Solid-phase crystallization of high growth rate amorphous silicon films deposited by gas-jet electron beam plasma CVD method

Formation of Si nanocrystals in SiOx, SiOx:C:H films and Si/SiO2multilayer nano-heterostructures by pulse laser treatments

Silicon Nanocrystals and Amorphous Nanoclusters in SiOx and SiNx: Atomic, Electronic Structure, and Memristor Effects

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Formation of Si nanocrystals in SiO_x, SiO_x:C:H films and Si/SiO₂multilayer nano-heterostructures by pulse laser treatments

Silicon Nanocrystals and Amorphous Nanoclusters in SiO_x and SiN_x: Atomic, Electronic Structure, and Memristor Effects