Temperature-induced obliteration of sub-oxide interfaces in amorphous GeO

Schacht, A.; Sternemann, Christian; Hohl, A.; Sternemann, H.; Sahle, Christoph J.; Paulus, Michael; Tolan, Metin

doi:10.1016/j.jnoncrysol.2009.04.040

Cited by 14 publications

(10 citation statements)

References 17 publications

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“…A sudden transition occurs after annealing at 700 °C, in which almost all the GeO 2 disappears, and the spectrum is dominated by a low-valent species Ge (spectrum 2-d). The energy onset and the spectral profile resembles the previously reported metallic Ge 2 28 . Unlike the fresh GeO x which has a mixture of metallic Ge and amorphous GeO 2 , air-exposed GeO x after 700 °C turns almost completely to metallic Ge.…”

Section: Resultssupporting

confidence: 85%

Reduced GeO2 Nanoparticles: Electronic Structure of a Nominal GeOx Complex and Its Stability under H2 Annealing

Zhao

Yang

McLeod

et al. 2015

Sci Rep

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A nominal GeOx (x ≤ 2) compound contains mixtures of Ge, Ge suboxides, and GeO2, but the detailed composition and crystallinity could vary from material to material. In this study, we synthesize GeOx nanoparticles by chemical reduction of GeO2, and comparatively investigate the freshly prepared sample and the sample exposed to ambient conditions. Although both compounds are nominally GeOx, they exhibit different X-ray diffraction patterns. X-ray absorption fine structure (XAFS) is utilized to analyse the detailed structure of GeOx. We find that the two initial GeOx compounds have entirely different compositions: the fresh GeOx contains large amorphous Ge clusters connected by GeOx, while after air exposure; the Ge clusters are replaced by a GeO2-GeOx composite. In addition, the two GeOx products undergo different structural rearrangement under H2 annealing, producing different intermediate phases before ultimately turning into metallic Ge. In the fresh GeOx, the amorphous Ge remains stable, with the GeOx being gradually reduced to Ge, leading to a final structure of crystalline Ge grains connected by GeOx. The air-exposed GeOx on the other hand, undergoes a GeO2→GeOx→Ge transition, in which H2 induces the creation of oxygen vacancies at intermediate stage. A complete removal of oxides occurs at high temperature.

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Section: Resultssupporting

confidence: 85%

Reduced GeO2 Nanoparticles: Electronic Structure of a Nominal GeOx Complex and Its Stability under H2 Annealing

Zhao

Yang

McLeod

et al. 2015

Sci Rep

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“…Further increases in temperature make the size of both Ge and GeO 2 domains grow. 25 The IR spectra of residues recovered from the alumina tube and at the coldfinger present bands in similar regions as quartzlike GeO 2 (Figure 7). The main absorption band centered at 879 cm −1 in quartz-like GeO 2 is assigned to the asymmetric Ge−O stretching band and it appears at higher wavenumbers in amorphous GeO 2 .…”

Section: ■ Results and Discussionmentioning

confidence: 83%

Framework Reduction of GeO₂ Zeolites During Calcination

Villaescusa

Camblor

2016

Chem. Mater.

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Calcination in air of GeO2 zeolites with AST-topology causes reduction of the framework, hence structural destruction, in a notable extension. This is due to the impossibility for the organic cation occluded inside to react with ambient oxygen. As the temperature increases, reoxidation in air of the reduced framework causes episodes of weight-gain. When calcination is carried out in N2, weight losses close to 70% imply a loss of Ge due to sublimation of germanium monoxide, GeO. The nature of the organic cation occluded determines the nature and oxidation state of the final residue after calcination in N2: for tetramethylammonium the residue is GeO2 while trimethyl-terc-butylammonium, thanks to its larger C content, yields metallic Ge. Framework organoreduction is not unique to GeO2-AST zeolites but also occurs during the calcination in air of other germanium-containing zeolites with larger pore openings.

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“…GeO x film is interesting to serve as a matrix and a precursor in the meantime for the formation of embedded Ge nanoclusters. Though GeO x films containing Ge nanocrystals have been prepared by several methods, [9][10][11] high temperatures were usually required. However, the high temperature processes degraded the resulting device structure and device performances.…”

Section: Introductionmentioning

confidence: 99%

Memory Characteristics of Metal-Oxide-Semiconductor Structures Based on Ge Nanoclusters-Embedded GeO_x Films Grown at Low Temperature

Lin¹,

Lou²,

Lee³

et al. 2012

j nanosci nanotechnol

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The memory devices constructed from the Ge-nanoclusters embedded GeO(x) layer deposited by the laser-assisted chemical vapor deposition (LACVD) system were fabricated. The Ge nanoclusters were observed by a high-resolution transmission electron microscopy. Using the capacitance versus voltage (C-V) and the conductance versus voltage (G-V) characteristics measured under various frequencies, the memory effect observed in the C-V curves was dominantly attributed to the charge storage in the Ge nanoclusters. Furthermore, the defects existed in the deposited film and the interface states were insignificant to the memory performances. Capacitance versus time (C-t) measurement was also executed to evaluate the charge retention characteristics. The charge storage and retention behaviors of the devices demonstrated that the Ge nanoclusters grown by the LACVD system at low temperature are promising for memory device applications.

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Temperature-induced obliteration of sub-oxide interfaces in amorphous GeO

Cited by 14 publications

References 17 publications

Reduced GeO2 Nanoparticles: Electronic Structure of a Nominal GeOx Complex and Its Stability under H2 Annealing

Reduced GeO2 Nanoparticles: Electronic Structure of a Nominal GeOx Complex and Its Stability under H2 Annealing

Framework Reduction of GeO₂ Zeolites During Calcination

Memory Characteristics of Metal-Oxide-Semiconductor Structures Based on Ge Nanoclusters-Embedded GeO_x Films Grown at Low Temperature

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Temperature-induced obliteration of sub-oxide interfaces in amorphous GeO

Cited by 14 publications

References 17 publications

Reduced GeO2 Nanoparticles: Electronic Structure of a Nominal GeOx Complex and Its Stability under H2 Annealing

Reduced GeO2 Nanoparticles: Electronic Structure of a Nominal GeOx Complex and Its Stability under H2 Annealing

Framework Reduction of GeO2 Zeolites During Calcination

Memory Characteristics of Metal-Oxide-Semiconductor Structures Based on Ge Nanoclusters-Embedded GeOx Films Grown at Low Temperature

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Product

Resources

About

Framework Reduction of GeO₂ Zeolites During Calcination

Memory Characteristics of Metal-Oxide-Semiconductor Structures Based on Ge Nanoclusters-Embedded GeO_x Films Grown at Low Temperature