Nanofilm versus Bulk Polymorphism in Wurtzite Materials

Demiroğlu, İlker; Bromley, Stefan T.

doi:10.1103/physrevlett.110.245501

Cited by 26 publications

(27 citation statements)

References 27 publications

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“…Our results both on the structural parameters and the energetics compare well with similar ab-initio calculations found in the literature [31][32][33][34]45 . …”

Section: Structural Propertiessupporting

confidence: 90%

“…Beyond bulk properties, the possibility of tuning electronic and optical properties through a reduction of dimensionality has fostered advances in the fabrication and structural characterization of ZnO nanostructures [13][14][15][16][17][18][19] and thin films on various substrates [20][21][22][23][24][25][26][27][28][29][30] , with a range of techniques and under a variety of experimental conditions. In particular in ultra-thin films, theoretical and experimental works indicate important variations of the atomic structure as a function of thickness [31][32][33][34] . However, to which extent the electronic properties are affected by these structural changes has not yet been investigated in detail.…”

Section: Introductionmentioning

confidence: 99%

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Confinement effects in ultrathin ZnO polymorph films: Electronic and optical properties

2016

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Relying on generalized-gradient and hybrid first-principles simulations, this work provides a complete characterization of the electronic properties of ZnO ultra-thin films, cut along the BodyCentered-Tetragonal(010), Cubane(100), h-BN(0001), Zinc-Blende(110), Wurtzite (1010) and (0001) orientations. The characteristics of the local densities of states are analyzed in terms of the reduction of the Madelung potential on under-coordinated atoms and surface states/resonances appearing at the top of the VB and bottom of the CB. The gap width in the films is found to be larger than in the corresponding bulks, which is assigned to quantum confinement effects. The components of the high frequency dielectric constant are determined and the absorption spectra of the films are computed. They display specific features just above the absorption threshold due to transitions from or to the surface resonances. This study provides a first understanding of finite size effects on the electronic properties of ZnO thin films and a benchmark which is expected to foster experimental characterization of ultra-thin films via spectroscopic techniques.

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“…Our results both on the structural parameters and the energetics compare well with similar ab-initio calculations found in the literature [31][32][33][34]45 . …”

Section: Structural Propertiessupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Confinement effects in ultrathin ZnO polymorph films: Electronic and optical properties

2016

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“…This reduction in polymorphic energy differences when going from bulk to nanofilm appears to be a general phenomenon that has been predicted to occur for a number of materials. 43 The new nanofilms NF1-NF4 found in our SMA searches all have energies slightly higher than the bixbyite nanofilm by 5.5-26.2 kJ mol −1 per Ce 2 O 3 . It is of note that the four nanofilms, NF1-NF4, have structures which do not correspond to any known bulk crystalline A 2 O 3 polymorph.…”

Section: Nanofilm Calculationsmentioning

confidence: 73%

Reduced ceria nanofilms from structure prediction

et al. 2015

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Experimentally, Ce2O3 films are used to study cerium oxide in its fully or partially reduced state, as present in many applications. We have explored the space of low energy Ce2O3 nanofilms using structure prediction and density functional calculations, yielding more than 30 distinct nanofilm structures. First, our results help to rationalize the roles of thermodynamics and kinetics in the preparation of reduced ceria nanofilms with different bulk crystalline structures (e.g. A-type or bixbyite) depending on the support used. Second, we predict a novel, as yet experimentally unresolved, nanofilm which has a structure that does not correspond to any previously reported bulk A2B3 phase and which has an energetic stability between that of A-type and bixbyite. To assist identification and fabrication of this new Ce2O3 nanofilm we calculate some observable properties and propose supports for its epitaxial growth.

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“…These can be taken from knowledge on an analogous system, in which case this techniques is called 'system comparison' [47]. This knowledge can be derived from a previous GO search, or from experimental information, e.g., on a systematics based on crystallographic principles or tiling theorems [38], etc.…”

Section: Structure Prediction Methodsmentioning

confidence: 99%

Atomistic and Electronic Structure Methods for Nanostructured Oxide Interfaces

Barcaro

Sementa

Negreiros

et al. 2016

Oxide Materials at the Two-Dimensional Limit

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An overview is given of methods for the computational prediction of the atomistic and electronic structures of nanoscale oxide interfaces. Global optimization approaches for structure prediction, together with total energy and electronic structure methods are reviewed and discussed. Our aim is to furnish conceptual instruments to select the optimal (i.e., the most accurate and least costly) method for treating a given system, and to understand the potentialities and limi-

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Nanofilm versus Bulk Polymorphism in Wurtzite Materials

Cited by 26 publications

References 27 publications

Confinement effects in ultrathin ZnO polymorph films: Electronic and optical properties

Confinement effects in ultrathin ZnO polymorph films: Electronic and optical properties

Reduced ceria nanofilms from structure prediction

Atomistic and Electronic Structure Methods for Nanostructured Oxide Interfaces

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