Visible photoluminescence of Ge microcrystals embedded in SiO2 glassy matrices

Maeda, Yoshihito; Tsukamoto, Nobuo; Yazawa, Y.; Kanemitsu, Yoshihiko; Masumoto, Yasuaki

doi:10.1063/1.105773

Cited by 610 publications

(328 citation statements)

References 11 publications

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“…Figure 2 shows the XPS of 8.8 at.% Ge/TiO 2 multi-layer. The spectrum of as-deposited film has only one peak of Ge 3d at 29.3 eV [4,5], and no other peak corresponding to Ge oxide was observed. On the other hand, the spectrum of annealed film has two broad peaks at 32.5 eV and 37.3 eV in addition to the main peak at 29.3eV.…”

Section: Methodsmentioning

confidence: 99%

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The Analysis Of Structure For The Multi-Layered Of Ge/TiO2 Films Prepared By The Differential Prressure Co-Sputtering

Adachi¹,

Abe²,

Matsuda³

et al. 2015

Archives of Metallurgy and Materials

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We tried to fabricate the Ge/TiO 2 composite films with the differential pressure (pumping) co-sputtering (DPCS) apparatus in order to improve the optical properties. In the study, the micro structure of these thin films has been evaluated. TEM image revealed that the thin film was alternately layered with TiO 2 and Ge, lattice fringes were observed both of Ge layer and TiO 2 layer. There were portions that lattice fringe of Ge was disturbed near the interface of Ge and TiO 2 . X-ray photoelectron spectroscopy elucidated that there were few germanium oxides and a part with the thin film after annealed.Keywords: TiO 2 , Ge, solar cells, sputtering W pracy przedstawiono rezultaty badań mających na celu wytworzenie warstw kompozytowych Ge/TiO 2 wykorzystując aparaturę do różnicowo-ciśnieniowego współrozpylania jonowego (DPCS) w celu poprawy właściwości optycznych. Mikrostruktura warstw została zbadana z zastosowaniem mikroskopii TEM. Analiza TEM wykazała, że cienki film składał się z naprzemiennie ułożonych warstw TiO 2 oraz Ge, a dodatkowo zlokalizowano krawędzie sieci przestrzennych Ge i TiO 2 . Rentgenowska spektroskopia fotoelektronów wykazała niewielkie ilości tlenków germanu oraz występowanie cienkiego filmu po procesie wyżarzania.

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Section: Methodsmentioning

confidence: 99%

“…On the other hand, the spectrum of annealed film has two broad peaks at 32.5 eV and 37.3 eV in addition to the main peak at 29.3eV. The broad peak at 32.5 eV [4,5] and 37.5 eV [6] correspond to Ge oxide such as GeO 2 , and Ti 3p, respectively. Even if oxidations of Ge were occurred in the thin film by annealing, it was very small.…”

Section: Methodsmentioning

confidence: 99%

The Analysis Of Structure For The Multi-Layered Of Ge/TiO2 Films Prepared By The Differential Prressure Co-Sputtering

Adachi¹,

Abe²,

Matsuda³

et al. 2015

Archives of Metallurgy and Materials

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“…[8,9] Generally, these physical methods produce particles with substantial size distributions, undesirable for applications that exploit size-dependent electronic properties. Bottom-up solution-phase synthetic chemistry methods offer better control of the size and shape of the nanoparticles, but often do not provide the good crystallinity required for many applications, and require the use of longchain ligands and surfactants to stabilize the particle surface and control growth.…”

Section: Synthesis Of Nanoamorphous Germanium and Itsmentioning

confidence: 99%

“…[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] The germanium sources in these investigations are usually the germanium halides, GeX n , or organogermanes [23,24] in which the Ge center is either in the 4 + or 2 + oxidation state (e.g., GeCl 4 , GeBr 4 , GeI 2 ), and long-chain phosphines and alkenes are often used as surface protection ligands for nanoparticle stabilization. The reducing agents used in these investigations are usually the strong ones, such as LiAlH 4 , NaBH 4 , sodium, sodium naphthalide, butyllithium, and Ge Zintl salts.…”

Section: Synthesis Of Nanoamorphous Germanium and Itsmentioning

confidence: 99%

Synthesis of Nanoamorphous Germanium and Its Transformation to Nanocrystalline Germanium

Dag

Henderson

Ozin

2012

Small

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A simple reaction between a mild reducing agent such as a trialkoxysilane and GeIV species such as germanium tetraalkoxides in a room‐temperature water/alcohol solution produces silica‐coated ultrasmall (2–3 nm) amorphous germanium nanoparticles (na‐Ge/SiO2). The initial reaction involves the straightforward hydrolysis and condensation of the precursors, Ge(OCH2CH3)4 and (CH3CH2O)3SiH, where the reaction rate depends on the water concentration in the reaction medium. These processes can be further accelerated by adding acid to the reaction medium or carrying out the reaction at higher temperatures. At low water contents (up to 50% water/ethanol) and low acid concentrations, the reaction proceeds as a clear solution, and no precipitation is observed. The initially colorless clear solution progressively changes to pale yellow, yellow, orange, red, and finally dark red as the na‐Ge particles grow. Evaporation of the solvent yields a reddish‐brown powder/monolith consisting of na‐Ge, embedded in an encapsulating amorphous silica matrix, na‐Ge/SiO2. The formation of na‐Ge proceeds extremely slowly and follows a first‐order dependence on both water concentration and diameter of the na‐Ge particles under the reaction conditions used. Annealing of the na‐Ge/SiO2 powder under an inert atmosphere at 600 °C produces ultrasmall germanium nanocrystals (nc‐Ge) embedded in amorphous silica (nc‐Ge/SiO2). Freestanding, colloidally stable nc‐Ge is obtained by chemical etching of the encapsulating silica matrix.

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“…A common method for preparing these systems is by alternate deposition of oxides and Ge, followed by an annealing process to increase the diffusion of nanocrystalites (NC) into the adjacent layers 4,6,7,8,9 . This process leads also to homogenize the sizes and spacial dispersion of NCs.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence of nanocrystals embedded in oxide matrices

Estrada¹,

Gonzalez²,

Kunold³

et al. 2007

Phys. Status Solidi (c)

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We used the theory of finite periodic systems to explain the photoluminescence spectra dependence on the average diameter of nanocrystals embedded in oxide matrices. Because of the broad matrix band gap, the photoluminescence response is basically determined by isolated nanocrystals and sequences of a few of them. With this model we were able to reproduce the shape and displacement of the experimentally observed photoluminescence spectra.

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Visible photoluminescence of Ge microcrystals embedded in SiO2 glassy matrices

Cited by 610 publications

References 11 publications

The Analysis Of Structure For The Multi-Layered Of Ge/TiO2 Films Prepared By The Differential Prressure Co-Sputtering

The Analysis Of Structure For The Multi-Layered Of Ge/TiO2 Films Prepared By The Differential Prressure Co-Sputtering

Synthesis of Nanoamorphous Germanium and Its Transformation to Nanocrystalline Germanium

Photoluminescence of nanocrystals embedded in oxide matrices

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