Structure analysis of new homologous compounds Ga2O3(ZnO)
 m
 (m = integer) by high-resolution analytical transmission electron microscopy

Li, Chunfei; Bando, Yoshio; Nakamura, Masaki; Kurashima, Keiji; Kimizuka, Noboru

doi:10.1107/s0108768198018424

Cited by 33 publications

(38 citation statements)

References 11 publications

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“…They are known to form a series of ordered structures known as homologous phases ͑ZnO͒ m ͑In 2 O 3 ͒, where m is an integer with m ജ 3. [25][26][27][28][29] Al-though homologous phases have not been reported for the ZnO-Al 2 O 3 system, it may be present as a metastable structure.…”

Section: A Origin Of Lattice Expansionmentioning

confidence: 99%

Atomic structures of supersaturated ZnO–Al2O3 solid solutions

Yoshioka

Oba

Huang

et al. 2008

Journal of Applied Physics

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Supersaturated ZnO-Al 2 O 3 ͑Ͼ20 at. % Al͒ thin films are grown by pulsed laser deposition technique on silica glass substrates at 600°C. They are characterized by combining x-ray diffraction, Al-K edge x-ray absorption near edge structures ͑XANESs͒, high resolution transmission electron microscope ͑TEM͒ imaging, TEM analysis, and a series of first principles calculations. The films are composed of textured wurtzite grains with c planes parallel to the substrate. The distance between c planes expands significantly when the Al concentration is greater than 10 at. %. The expansion disappears after annealing the films at above 800°C. High density of dislocationlike defects is found in the as deposited film. Any segregation of Al cannot be detected either at the grain boundaries or inside the grains. The lattice expansion toward c axis and the experimental XANES can be satisfactorily explained by taking a hypothetical homologous model with the composition of ͑ZnO͒ 3 ͑Al 2 O 3 ͒ as the local environment of Al in the supersaturated solid solution. Simplified substitutional models with Al at the Zn site in wurtzite ZnO cannot explain these experimental results. First principles calculations show that the homologous phase is energetically more favorable than the simplified substitutional models, although decomposition into ZnO and ZnAl 2 O 4 is more favorable than the homologous phase. The local atomic structures of the supersaturated solid solution are therefore concluded to be analogous to the metastable homologous phase.

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Section: A Origin Of Lattice Expansionmentioning

confidence: 99%

Atomic structures of supersaturated ZnO–Al2O3 solid solutions

Yoshioka

Oba

Huang

et al. 2008

Journal of Applied Physics

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“…The exact temperature required depends on the composition and the desired products [99][100][101][102][103]. A large number of syntheses have been performed; and crystal structures were first reported for R = In and Ga, with different M .…”

Section: Rules Governing Structure Formation Crystalline Multi-componmentioning

confidence: 99%

Multi-component transparent conducting oxides: progress in materials modelling

Walsh

Silva

Wei

2011

J. Phys.: Condens. Matter

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Transparent conducting oxides (TCOs) play an essential role in modern optoelectronic devices through their combination of electrical conductivity and optical transparency. We review recent progress in our understanding of multi-component TCOs formed from solid-solutions of ZnO, In2O3, Ga2O3 and Al2O3, with a particular emphasis on the contributions of materials modelling, primarily based on Density Functional Theory. In particular, we highlight three major results from our work: (i) the fundamental principles governing the crystal structures of multi-component oxide structures including (In2O3)(ZnO)n, named IZO, and (In2O3)m(Ga2O3) l (ZnO)n, named IGZO; (ii) the relationship between elemental composition and optical and electrical behaviour, including valence band alignments; (iii) the high-performance of amorphous oxide semiconductors. From these advances, the challenge of the rational design of novel electroceramic materials is discussed.PACS numbers: 71.15.Mb

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“…A number of oxide semiconductors form superlattices naturally. These include In2O3(ZnO)k [10][11][12][13][14][15][16][17], CaO(CaMnO3)k [18,19], NaxCo2O4 [20,21] and Ga2O3(ZnO)k [22][23][24], where the integer k denotes the order of the superlattice structure. In the ZnO-based superlattices the integer k describes the number of ZnO planes between the indium oxide layers [13,17,25] measured along the c-axis of the ZnO.…”

Section: Introductionmentioning

confidence: 99%

Single layer In-O atomic sheets as phonon and electron barriers in ZnO-In2O3 natural superlattices: Implications for thermoelectricity

Liang

Clarke

2018

Journal of Applied Physics

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The phases in the ZnO half of the ZnO-In2O3 binary system are natural superlattices consisting of periodic stacking of single InO2 sheets separated by indium doped ZnO blocks with a spacing that depends on the composition according to the relationship In2O3(ZnO)k.Characterization by combined, atomic resolution, aberration-corrected scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) analysis, indicates that the atomic structure of each InO2 layer consists of a single continuous sheet of octahedrally-coordinated InO2. The sheets also are crystallographic inversion boundaries. Analysis of the electrical conductivity, thermal conductivity and Seebeck coefficient data at 800 o C indicates that the InO2 sheets not only decrease thermal conductivity by phonon scattering but also create potential barriers to electron transport. The origin of the potential barriers, the role of piezoelectric effects and their dependence on superlattice spacing is discussed qualitatively. It is also argued that the crystallographically-aligned InO2 sheets within individual grains are also transport barriers in randomly oriented polycrystalline materials.

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Structure analysis of new homologous compounds Ga₂O₃(ZnO) _m (m = integer) by high-resolution analytical transmission electron microscopy

Cited by 33 publications

References 11 publications

Atomic structures of supersaturated ZnO–Al2O3 solid solutions

Atomic structures of supersaturated ZnO–Al2O3 solid solutions

Multi-component transparent conducting oxides: progress in materials modelling

Single layer In-O atomic sheets as phonon and electron barriers in ZnO-In2O3 natural superlattices: Implications for thermoelectricity

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Structure analysis of new homologous compounds Ga2O3(ZnO) m (m = integer) by high-resolution analytical transmission electron microscopy

Cited by 33 publications

References 11 publications

Atomic structures of supersaturated ZnO–Al2O3 solid solutions

Atomic structures of supersaturated ZnO–Al2O3 solid solutions

Multi-component transparent conducting oxides: progress in materials modelling

Single layer In-O atomic sheets as phonon and electron barriers in ZnO-In2O3 natural superlattices: Implications for thermoelectricity

Contact Info

Product

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Structure analysis of new homologous compounds Ga₂O₃(ZnO) _m (m = integer) by high-resolution analytical transmission electron microscopy