Permanent densification of amorphous zinc oxide under pressure: A first principles study

Tahaoğlu, Duygu; Durandurdu, Murat

doi:10.1016/j.jnoncrysol.2017.10.016

Cited by 5 publications

(2 citation statements)

References 24 publications

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“…Amid largely unsuccessful attempts to grow good quality a‐ZnO films, theoretical predictions of a‐ZnO have been more optimistic. Stable a‐ZnO structures have been produced using mainly ab initio molecular dynamics (MD) melt and quench (MQ) methods . These computationally demanding calculations use small periodic cells, very high cooling rates, and provide limited statistics of structural characteristics.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Intrinsic Electron and Hole Trapping in Crystalline and Amorphous ZnO

Mora‐Fonz

Shluger

2019

Adv Elect Materials

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Furthermore, even thermodynamically stable phases, for example, zincblende or rocksalt, are only grown under very specific conditions of substrates and/or at high pressure (see, e.g., refs. [8-12]). Although successful growth of thin a-ZnO films with thicknesses ranging from 5 to 100 nm using different techniques and on different substrates has been reported, [13-18] the morphology of these films remains controversial due to the lack of high intensity X-ray diffraction or grazing incidence X-ray and neutron diffraction characterization. Many of such films are reported to contain nanocrystalline inclusions. [13,16,18-20] Amid largely unsuccessful attempts to grow good quality a-ZnO films, theoretical predictions of a-ZnO have been more optimistic. Stable a-ZnO structures have been produced using mainly ab initio molecular dynamics (MD) melt and quench (MQ) methods. [21-26] These computationally demanding calculations use small periodic cells, very high cooling rates, and provide limited statistics of structural characteristics. The sampling of the a-ZnO configurational space has been, therefore, poor and a distribution of electronic properties has not been provided yet. Recently, we investigated the ability of bulk ZnO to form glass structures using interatomic potentials (IPs) and an MQ procedure within isothermal-isobaric (NPT) ensemble. [27] This allowed us to use large (up to 768 000 atoms) periodic cells and improve the statistics of the distribution of a-ZnO structural characteristics. These calculations have demonstrated that cooling rates in an MQ procedure around 100 K ps −1 lead to the formation of stable and uniform amorphous structures. ZnO samples show, however, different degrees of crystallinity at lower cooling rates. The average density of a-ZnO samples produced using IPs is about 5.04 g cm −3 and the coordination numbers of Zn and O atoms are around 3.9, reflecting the strong propensity to crystallization. Still, the stability tests carried out using the activation-relaxation technique (ART) [28-32] and simulated annealing demonstrated that the obtained amorphous structures are stable. [27] Advances in ultrafast liquid quenching and deposition of thin films on cold substrates [33-36] make achieving growth of amorphous ZnO films a tangible prospect. Their potential use in (photo)electronic devices will expose these films to electrons and holes. Therefore, questions arise whether a-ZnO films will retain good electron mobility and whether there is any possibility for electron or hole localization due to disorder. Such Recent advances in ultrafast liquid quenching and deposition of thin films on cold substrates make growing amorphous (a)-ZnO films increasingly feasible. The electronic structure and electron and hole trapping properties of amorphous ZnO are predicted using density functional theory (DFT) simulations with a hybrid density functional (h-DFT). An ensemble of fifty 324-atom structures is employed to obtain the distribution of structural and electronic properties of a-ZnO. The results demon...

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Section: Introductionmentioning

confidence: 99%

Modeling of Intrinsic Electron and Hole Trapping in Crystalline and Amorphous ZnO

Mora‐Fonz

Shluger

2019

Adv Elect Materials

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“…Study the pressure-induced piezoelectric, elastic, infrared and Raman behaviors of ZnO wurtzite structure. Permanent densification of amorphous zinc oxide under pressure: first-principles analysis (Tahaoğlu and Durandurdu, 2018). Moreover, there are many works about ZnO structural, electrical and vibrational properties and performances as a function of pressure (Serrano and Romero,2004;Pellicer-Porres et al,2011;Saitta and Decremps, 2004).…”

Section: Introductionmentioning

confidence: 99%

Study the Influence of High Pressure on the Optical and Electronic Properties of Composite ZnO Using (DFT-GGA)

Shihatha¹,

Ghaleb²,

Munef³

2021

RJS

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In this article, the lattice constants, band structure and optical characteristics of ZnO wurtzite structure under various pressures were studied using the generalized gradient approximation (GGA) method. This method is based on the functional density (DFT) Theory, according to the first principle. The results show that as the pressure increases and the band gap increases, the lattice constants (a and c) decrease. As the pressure increases, the minimum conduction band will move to a higher energy level, and the maximum valence band will move to a lower energy level, thereby increasing the energy band difference. As the pressure increases, the shape of the optical parameter curve remains almost unchanged, and all peaks move to higher energies. The state density, dielectric function, reflectance and absorption coefficient are also calculated. The overview of the spectrum and optical properties is discussed, including the imaginary part of the dielectric function, reflectance and absorption coefficient of wurtzite-type ZnO under environmental conditions. The optical constants indicate that the phase of ZnO wurtzite structure is transparent. We noticed that our measurements are comparable to those observed in the literature.

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Effect of Mg content on electronic structure, optical and structural properties of amorphous ZnO nanoparticles: A DFTB study

Kurban

Alaei

Kurban

2021

Journal of Non-Crystalline Solids

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Permanent densification of amorphous zinc oxide under pressure: A first principles study

Cited by 5 publications

References 24 publications

Modeling of Intrinsic Electron and Hole Trapping in Crystalline and Amorphous ZnO

Modeling of Intrinsic Electron and Hole Trapping in Crystalline and Amorphous ZnO

Study the Influence of High Pressure on the Optical and Electronic Properties of Composite ZnO Using (DFT-GGA)

Effect of Mg content on electronic structure, optical and structural properties of amorphous ZnO nanoparticles: A DFTB study

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