Local structures of polar wurtzites<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Zn</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>Mg</mml:mtext></mml:mrow><mml:mi>x</mml:mi></mml:msub><mml:mtext>O</mml:mtext></mml:mrow></mml:math>studied by Raman and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscri

Kim, Young Il; Cadars, Sylvian; Shayib, Ramzy; Proffen, Thomas; Feigerle, C. S.; Chmelka, Bradley F.; Seshadri, Ram

doi:10.1103/physrevb.78.195205

Cited by 47 publications

(13 citation statements)

References 42 publications

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“…Significant changes in the ionic polarization were observed (from −5.6 µC cm −2 for x = 0 to −4.8 µC cm −2 for x = 0.15), despite only subtle increments in the cell volume (∼0.03%) and the planar areal dimension (∼0.1%). In addition to synchrotron x-ray diffraction, Raman spectroscopy, NMR and neutron scattering were also applied [251,252]; the results suggest that Mg substitution will increase the spontaneous polarization of ZnO.…”

Section: Synthesis and Characterization Of Mgzno And Cdzno Alloysmentioning

confidence: 99%

Fundamentals of zinc oxide as a semiconductor

2009

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In the past ten years we have witnessed a revival of, and subsequent rapid expansion in, the research on zinc oxide (ZnO) as a semiconductor. Being initially considered as a substrate for GaN and related alloys, the availability of high-quality large bulk single crystals, the strong luminescence demonstrated in optically pumped lasers and the prospects of gaining control over its electrical conductivity have led a large number of groups to turn their research for electronic and photonic devices to ZnO in its own right. The high electron mobility, high thermal conductivity, wide and direct band gap and large exciton binding energy make ZnO suitable for a wide range of devices, including transparent thin-film transistors, photodetectors, light-emitting diodes and laser diodes that operate in the blue and ultraviolet region of the spectrum. In spite of the recent rapid developments, controlling the electrical conductivity of ZnO has remained a major challenge. While a number of research groups have reported achieving p-type ZnO, there are still problems concerning the reproducibility of the results and the stability of the p-type conductivity. Even the cause of the commonly observed unintentional n-type conductivity in as-grown ZnO is still under debate. One approach to address these issues consists of growing high-quality single crystalline bulk and thin films in which the concentrations of impurities and intrinsic defects are controlled. In this review we discuss the status of ZnO as a semiconductor. We first discuss the growth of bulk and epitaxial films, growth conditions and their influence on the incorporation of native defects and impurities. We then present the theory of doping and native defects in ZnO based on density-functional calculations, discussing the stability and electronic structure of native point defects and impurities and their influence on the electrical conductivity and optical properties of ZnO. We pay special attention to the possible causes of the unintentional n-type conductivity, emphasize the role of impurities, critically review the current status of p-type doping and address possible routes to controlling the electrical conductivity in ZnO. Finally, we discuss band-gap engineering using MgZnO and CdZnO alloys.

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Section: Synthesis and Characterization Of Mgzno And Cdzno Alloysmentioning

confidence: 99%

Fundamentals of zinc oxide as a semiconductor

2009

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“…85 Mg 0.15 O from which it was difficult to extract any NMR parameters, but it did appear that the intensity was around À30 to À40ppm. 144 The MgO 4 unit is expected to be quite distorted so significant second-order quadrupole effects could be shifting the resonance well away from the isotropic chemical shift. Also the 12 next nearest neighbours will be a range of combinations of zinc and magnesium, and these could also be having an effect on the electron density and hence the shielding of the nucleus.…”

Section: Oxide-based Crystalline Inorganic Materialsmentioning

confidence: 99%

Recent Advances in Solid-State 25Mg NMR Spectroscopy

Freitas

Smith

2012

Annual Reports on NMR Spectroscopy

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“…In order to do so, the indium, gallium, and zinc polyhedra, obtained from the amorphous phase, are compared with the polyhedra from the various crystalline systems of indium oxides [40], gallium oxides [41,42], zinc oxides [43][44][45], and crystalline InGaZnO 4 [46,47]. All these crystalline polyhedral templates are depicted in Fig.…”

Section: Methodology For Comparing Polyhedramentioning

confidence: 99%

Recurring polyhedral motifs in the amorphous indium gallium zinc oxide network

Divya

Prasad

2017

Phys. Status Solidi A

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The coordination polyhedra around the cations are the building blocks of ionic solids. For amorphous InGaZn oxide (a‐IGZO), these coordination polyhedra are identified to investigate properties that depend on short range interactions. Therefore, in this first principles based study, a large number (10) of samples of a‐IGZO were prepared by ab initio melt‐and‐quench molecular dynamics, so that several distinct samples of the amorphous landscape are obtained corresponding to local minima in energy. Based on a method of comparing bond angles between metal and oxygen atoms, the identified polyhedra were matched to the polyhedral motifs present in the related crystalline systems, such as, InGaZnO4, In2O3, Ga2O3, and ZnO. Consequently, we find, the a‐IGZO primarily consists of the following polyhedra: a tetrahedron from space group 199 and an octahedron from space group 206 of In2O3; a tetrahedron from space group 12 and an octahedron from space group 167 of Ga2O3; a tetrahedron from space group 186 of ZnO; zinc and gallium trigonal bipyramids from c‐IGZO; and one zinc fourfold, one zinc fivefold, and one indium fivefold coordination polyhedra that occur only in the amorphous phase. Thus, we were able to reduce the description of structure from 360 to 10 groups of polyhedra.

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Local structures of polar wurtzitesZn1−xMgxOstudied by Raman and

Cited by 47 publications

References 42 publications

Fundamentals of zinc oxide as a semiconductor

Fundamentals of zinc oxide as a semiconductor

Recent Advances in Solid-State 25Mg NMR Spectroscopy

Recurring polyhedral motifs in the amorphous indium gallium zinc oxide network

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