Local vibration at the surface of a Ge nanocrystal embedded in a silicon oxide matrix

Yang, Yimin; Wu, Xiaolan; Yang, Luwei; Huang, G.S.; Qiu, Teng; Yi, Shaohua; Siu, G. G.; Chu, Paul K.

doi:10.1063/1.2150594

Cited by 11 publications

(7 citation statements)

References 18 publications

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“…A typical Raman spectrum in the range of 10-700 cm −1 is shown in Fig. 1(b) from which it can be inferred that the formed particles are Ge NCs and the data are consistent with those produced by x-ray diffractions [13,14]. In Fig.…”

supporting

confidence: 78%

“…In this work, low-frequency Raman scattering from Ge NCembedded amorphous silica films is investigated. The low-frequency Raman peak, which is not affected by the NC size, is found to depend on the interfacial structure [13], and a modified core-shell-matrix model is proposed to explain the observed results. SiO 2 / SiO 2 : Ge: Si/ SiO 2 samples about 3 m thick were prepared on cleaned Si (100) substrates [13].…”

mentioning

confidence: 83%

“…The low-frequency Raman peak, which is not affected by the NC size, is found to depend on the interfacial structure [13], and a modified core-shell-matrix model is proposed to explain the observed results. SiO 2 / SiO 2 : Ge: Si/ SiO 2 samples about 3 m thick were prepared on cleaned Si (100) substrates [13]. In our experiment, the Ge and Si chips were placed on a large silica target and then cosputtered using 1 Pa Ar gas at 140 W power and room temperature.…”

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confidence: 83%

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Size-independent low-frequency Raman scattering in Ge-nanocrystal-embedded SiO_2 films

Liu

Gao

et al. 2010

Opt. Lett.

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The peak position and linewidth of the low-frequency Raman mode observed from amorphous silica films embedded with Ge nanocrystals doped with Si show a size-independent behavior. Spectral analysis reveals the formation of a thin amorphous GeSi layer on the surface of the Ge nanocrystal. Theoretical calculation based on a modified three-region model discloses that the acoustic impedance of the interfacial GeSiO layer is responsible for the size-independent behavior. During high-temperature annealing, Ge atoms are segregated from the interface into the core, and the GeSiO interface layer is converted to SiO(2), leading to disappearance of the size-independent vibration mode.

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confidence: 78%

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confidence: 83%

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confidence: 83%

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Size-independent low-frequency Raman scattering in Ge-nanocrystal-embedded SiO_2 films

Liu

Gao

et al. 2010

Opt. Lett.

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“…It was shown that depending on the experimental conditions it is often possible to control the crystallization process and obtain transparent nanocrystallized glasses that may have a high potential for applications in photonic devices [1][2][3][4]. It was also shown that a solid matrix may significantly change the properties of the nanoparticles [4][5][6]. On the other hand, existence of nanoparticles has a major effect on the host matrix.…”

Section: Introductionmentioning

confidence: 97%

Studies of nanostructuring in cesium magnesium tungsten phosphate glass

Mączka

Kępiński

Hanuza

et al. 2007

Journal of Non-Crystalline Solids

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Cs 2 O-MgO-WO 3 -P 2 O 5 glass was examined in a broad temperature range using heat capacity, Raman and Brillouin scattering methods. The main aim was to study the elastic properties of the as-prepared glass, the mechanism of nanostructuring in this material and the influence of nanostructuring on its elastic properties. It was shown that this glass exhibits prominent nanocrystallization during thermal treatment, giving Cs(Mg 0.25 W 1.75 )O 6 nanocrystals with the size of 4-10 nm. The crystallization process was hindered when crystallinity reached about 14 ± 0.6 wt%. The origin of this behavior was discussed. It was also demonstrated that the elastic properties are largely improved by nanocrystallization.

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“…Furthermore, the optimal PL performance was obtained when SiC deposited time was 1 h and the glass substrate was etched for 20 min in the annealing sample (450 o C). [2][3][4][5][6][7] , the porous SiC [8,9] , the rare-earth doped SiC [10][11][12] and the SiO 2 -related materials [13] , have been extensively studied. Among them, silicon carbide has attracted special interests because it has potential applications on optoelectronics devices and high-temperature mechanical devices.…”

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confidence: 99%

Investigation of luminescence from SiC nano-granule films on porous glass substrate

Zhen

Zhang

Wang

et al. 2008

Optoelectron. Lett.

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SiC granule films were fabricated onto porous glass substrate by RF-magnetron sputtering. Photoluminescence (PL) measurements show that there are light emissions at three different wavelengths. Ultraviolet emission peaked at 360 nm originated from the band-band transmission of SiC nanoparticles with relatively small size. The 370 nm light emission was due to the luminescence of the nano-skeletons of porous glass that was formed during the etching of the glass substrate. The blue emission at about 460 nm was associated with the recombination of the excited electron and O-deficient defects appeared at the interface between SiC nanoparticles and the porous glass. Furthermore, the optimal PL performance was obtained when SiC deposited time was 1 h and the glass substrate was etched for 20 min in the annealing sample (450 o C). [2][3][4][5][6][7] , the porous SiC [8,9] , the rare-earth doped SiC [10][11][12] and the SiO 2 -related materials [13] , have been extensively studied. Among them, silicon carbide has attracted special interests because it has potential applications on optoelectronics devices and high-temperature mechanical devices. Tan et al. [14,15] have fabricated -SiC films containing both SiC and Si nanocrystallites. Blue emissions at two distinct wavelengths were explained by the radiative recombination of carriers taking place in a kind of silicon excess defect centers at the surfaces of SiC crystallites, whereas the photogeneration of carriers partially occured in the SiC crystallite cores. Liu et al. [16] have also fabricated SiC nanocrystals embedded in SiO 2 matrix by radio-frequency (RF) sputtering and high-temperature annealing. In the case, the observed blue luminescence and green luminescence were thought to originate from the SiC nanoparticle and C nanocluste, respectively. On the other hand, Wang et al. [17] have fabricated SiC/Si/SiO 2 multi-layer films. Two PL peaks were attributed to excess Si defect centers and SiC nanocrystalline. Although many studies have been carried out in order to explain the origin of the luminescence of the indirect-gap group-IV semiconductor and the expected effective light emission, the PL mechanism of SiC-based materials still remains an open question.In the present work, SiC nano-granule films onto the porous glass substrate were fabricated for the first time by RFsputtering technique. Such a special structure gives rise to unique photoluminescence performance. In the experiment, ultraviolet (UV) emission peaked at 360 nm, 370 nm and the blue emission peaked at about 460 nm were observed. Their luminescence mechanism was further discussed in this paper. According to our knowledge, it is the first report about the photoluminescence study of such a structure.The SiC films were prepared on the porous glass substrate by a conventional RF-magnetron sputtering technique. Before the deposition, the glass substrate was dipped in hydrofluoric acid for different time (10 min, 20 min and 30 min) to form porous structures. The substrate was then ultrasonicly cleaned in eth...

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Local vibration at the surface of a Ge nanocrystal embedded in a silicon oxide matrix

Cited by 11 publications

References 18 publications

Size-independent low-frequency Raman scattering in Ge-nanocrystal-embedded SiO_2 films

Size-independent low-frequency Raman scattering in Ge-nanocrystal-embedded SiO_2 films

Studies of nanostructuring in cesium magnesium tungsten phosphate glass

Investigation of luminescence from SiC nano-granule films on porous glass substrate

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