Ab Initio Hartree-Fock Simulation of R-Plane Sapphire

Stirner, T.; Sun, Jingjing; Aust, Martin

doi:10.1016/j.phpro.2012.03.611

Cited by 12 publications

(9 citation statements)

References 32 publications

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“…2(f,g) ), but persists in the MoS 2 on r-sapphire, suggesting that the S-O bond is fundamentally different between the two growth substrates. The S-O bond on c-sapphire is likely due to unsulfurized MoO x S 2−x , while the S-O bond on r-sapphire is more likely to be from S bonded with the top O-terminated sapphire due to the weak O-O bond in sapphire 43 and strong interfacial interaction when O is terminated on the r-sapphire surface 44 . Additionally, the Mo-O bonding on r-sapphire is significantly reduced (Fig.…”

Section: Resultsmentioning

confidence: 99%

Deconvoluting the Photonic and Electronic Response of 2D Materials: The Case of MoS2

Zhang

Borys

Bersch

et al. 2017

Sci Rep

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Evaluating and tuning the properties of two-dimensional (2D) materials is a major focus of advancing 2D science and technology. While many claim that the photonic properties of a 2D layer provide evidence that the material is “high quality”, this may not be true for electronic performance. In this work, we deconvolute the photonic and electronic response of synthetic monolayer molybdenum disulfide. We demonstrate that enhanced photoluminescence can be robustly engineered via the proper choice of substrate, where growth of MoS2 on r-plane sapphire can yield >100x enhancement in PL and carrier lifetime due to increased molybdenum-oxygen bonding compared to that of traditionally grown MoS2 on c-plane sapphire. These dramatic enhancements in optical properties are similar to those of super-acid treated MoS2, and suggest that the electronic properties of the MoS2 are also superior. However, a direct comparison of the charge transport properties indicates that the enhanced PL due to increased Mo-O bonding leads to p-type compensation doping, and is accompanied by a 2x degradation in transport properties compared to MoS2 grown on c-plane sapphire. This work provides a foundation for understanding the link between photonic and electronic performance of 2D semiconducting layers, and demonstrates that they are not always correlated.

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Section: Resultsmentioning

confidence: 99%

Deconvoluting the Photonic and Electronic Response of 2D Materials: The Case of MoS2

Zhang

Borys

Bersch

et al. 2017

Sci Rep

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“…Among them, the interface between the CuAlO 2 nucleus and the alumina/sapphire substrate probably plays a major role. The (0001) sapphire surface has the lowest surface energy among the four low index surfaces of (0001), (112̅0), (101̅0), and (11̅02) . The interfacial energy of the (0001) CuAlO2 /(0001) sapphire interface may be also to the lowest among all possible combinations.…”

Section: Resultsmentioning

confidence: 98%

“…The (0001) sapphire surface has the lowest surface energy among the four low index surfaces of (0001), (112̅ 0), (101̅ 0), and (11̅ 02). 31 The interfacial energy of the (0001) CuAlO2 / (0001) sapphire interface may be also to the lowest among all possible combinations. In addition, no epitaxy between CuAlO 2 and sapphire is observed.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Substrate-Induced Anisotropic Growth of CuAlO₂ Platelets in a Liquid–Solid Reaction

et al. 2023

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This study reports a simplified method to grow CuAlO2 crystals of submillimeter sizes with a highly anisotropic shape of a platelet. The solid-state reaction of forming CuAlO2 at ca. 1373 K in the first stage of the conventional flux method is no longer required. The CuAlO2 platelets nucleated directly onto the (0001)sapphire surface in a melt of Cu2O saturated with Al2O3 at 1473 K. The excess flux was mostly removed by the capped alumina plate on cooling with a limited amount of residue which can be leached afterward. The CuAlO2 platelets all have a 3R crystal structure with no line and planar defects observed by TEM. The CuAlO2 crystals emit a luminescence at 3.49 eV associated with resonant Raman effect resulted from a band-to-band transition in room-temperature PL measurement. The facile fabrication method for growing highly anisotropic CuAlO2 crystals paves the way for their practical application in photoelectrochemical devices.

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“…Consequently, understanding the mechanical behavior of alumina in different service conditions has been an active area of study for researchers to date. For instance, Young's modulus, fracture behavior, tensile and compressive strength, and thermal properties of polycrystalline alumina and single crystal alumina or sapphire have been widely evaluated both experimentally and through modeling approaches …”

Section: Introductionmentioning

confidence: 99%

Multiscale Modeling of the Nanodefects and Temperature Effect on the Mechanical Response of Sapphire

2016

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A multiscale approach using Bridging Cell Method (BCM) is applied to simulate the combined effect of temperature and alumina's common structural nanodefects such as nanovoids, precracks, and Mg impurities on the mechanical response of single crystal C-plane and M-plane sapphire. The BCM model consists of three domains of continuum, bridging, and atomistic, where the whole system is solved in a finite element (FE) framework. Interatomic interaction potentials and temperaturedependent formulations are incorporated in the atomistic domain to conduct simulations for structures containing nanodefects at a range of finite temperatures from 300 to 1600 K. The results are compared for each case to analyze the effect of temperature and nanodefects. Mechanical response of the material is presented and discussed with respect to ultimate tensile strength (UTS), stress distribution and elasticity. Results show different material behavior for C-plane and M-plane under the same biaxial loading conditions but containing different nanodefects. Precracks are found to be the most critical defects for both systems, which significantly reduce structural strength. J ournalcontinuum domain boundary and V k , A k , and t k are volume, area, and traction of element k, respectively.Having E c calculated, the stiffness of the continuum domain, K c , could be obtained as:

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Ab Initio Hartree-Fock Simulation of R-Plane Sapphire

Cited by 12 publications

References 32 publications

Deconvoluting the Photonic and Electronic Response of 2D Materials: The Case of MoS2

Deconvoluting the Photonic and Electronic Response of 2D Materials: The Case of MoS2

Substrate-Induced Anisotropic Growth of CuAlO₂ Platelets in a Liquid–Solid Reaction

Multiscale Modeling of the Nanodefects and Temperature Effect on the Mechanical Response of Sapphire

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Ab Initio Hartree-Fock Simulation of R-Plane Sapphire

Cited by 12 publications

References 32 publications

Deconvoluting the Photonic and Electronic Response of 2D Materials: The Case of MoS2

Deconvoluting the Photonic and Electronic Response of 2D Materials: The Case of MoS2

Substrate-Induced Anisotropic Growth of CuAlO2 Platelets in a Liquid–Solid Reaction

Multiscale Modeling of the Nanodefects and Temperature Effect on the Mechanical Response of Sapphire

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Product

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Substrate-Induced Anisotropic Growth of CuAlO₂ Platelets in a Liquid–Solid Reaction