Molecular beam epitaxy

Joyce, B.A.

doi:10.1088/0034-4885/48/12/002

Cited by 204 publications

(57 citation statements)

References 163 publications

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“…These discoveries have been facilitated by the use of advanced growth techniques such as molecular-beam epitaxy (MBE) , [14] pulsed laser deposition (PLD) , [15] chemical vapour deposition (CVD) [16] and atomic layer deposition (ALD) [17] that have made-possible the deposition of single crystalline thin films with atomic level precision.…”

Section: Introductionmentioning

confidence: 99%

Interesting Evidence for Template‐Induced Ferroelectric Behavior in Ultra‐Thin Titanium Dioxide Films Grown on (110) Neodymium Gallium Oxide Substrates

Deepak

Miguel

Keeney

et al. 2014

Adv Funct Materials

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This paper reports the first-ever presentation of evidence for room-temperature ferroelectric behavior in anatase-phase titanium dioxide (a-TiO2). It is shown that behaviour strongly indicative of ferroelectric behavior is induced in ultra-thin (20nm to 80nm) biaxially-strained epitaxial films of a-TiO2 deposited by liquid injection chemical vapour deposition onto (110) Submitted to neodymium gallium oxide (NGO) substrates. The structural properties of the films were analyzed by x-ray diffraction and high-resolution transmission electron microscopy, which showed significant orthorhombic strain in films. Possible ferroelectric behavior was probed by piezoresponse force microscopy (PFM). The films on NGO showed a switchable dielectric spontaneous polarization, the ability to retain polarization information written into the film using the PFM tip for extended periods (several hours) and at elevated temperatures (up to 100°C) without significant loss, and the disappearance of the polarization at a temperature between 180 and 200°C, indicative of a Curie temperature within this range. This combination of effects is believed to constitute strong experimental evidence for ferroelectric behavior, which has not hitherto been reported in a-TiO2 and opens up the possibility for a range of new devices and materials applications. A model is presented for the effects of large in-plane strains on the crystal structure of anatase which provides a possible explanation for the experimental observations.

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Section: Introductionmentioning

confidence: 99%

Interesting Evidence for Template‐Induced Ferroelectric Behavior in Ultra‐Thin Titanium Dioxide Films Grown on (110) Neodymium Gallium Oxide Substrates

Deepak

Miguel

Keeney

et al. 2014

Adv Funct Materials

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“…A standard example of this scenario is molecular-beam epitaxy (MBE) [1][2][3][4][5][6], wherein a crystalline film is formed on an underlying crystalline substrate as the result of the deposition of new material from a molecular beam. The simplest experimental realization of MBE is homoepitaxial growth, in which the substrate and film are the same material.…”

Section: Introductionmentioning

confidence: 99%

Renormalization of stochastic lattice models: Epitaxial surfaces

Haselwandter

Vvedensky

2008

Phys. Rev. E

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We present the application of a method [Phys. Rev. E 76, 041115 (2007)] for deriving stochastic partial differential equations from atomistic processes to the morphological evolution of epitaxial surfaces driven by the deposition of new material. Although formally identical to the one-dimensional (1D) systems considered previously, our methodology presents substantial new technical issues when applied to two-dimensional (2D) surfaces. Once these are addressed, subsequent coarse-graining is accomplished as before by calculating renormalization-group (RG) trajectories from initial conditions determined by the regularized atomistic models. Our applications are to the EdwardsWilkinson (EW) model [Proc. Roy. Soc. London Ser. A 381, 17 (1982)], the Wolf-Villain (WV) model [Europhys. Lett. 13, 389 (1990)], and a model with concurrent random deposition and surface diffusion. With our rules for the EW model no appreciable crossover is obtained for either 1D or 2D substrates. For the 1D WV model, discussed previously, our analysis reproduces the crossover sequence known from kinetic Monte Carlo (KMC) simulations, but for the 2D WV model, we find a transition from smooth to unstable growth under repeated coarse-graining. Concurrent surface diffusion does not change this behavior, but can lead to extended transient regimes with kinetic roughening. This provides an explanation of recent experiments on Ge(001) with the intriguing conclusion that the same relaxation mechanism responsible for ordered structures during the early stages of growth also produces an instability at longer times that leads to epitaxial breakdown. The RG trajectories calculated for concurrent random deposition and surface diffusion reproduce the crossover sequences observed with KMC simulations for all values of the model parameters, and asymptotically always approach the fixed point corresponding to the equation proposed by Villain [J. Phys. I 1, 19 (1991)] and by Lai and Das Sarma [Phys. Rev. Lett. 66, 2899 (1991)]. We conclude with a discussion of the application of our methodology to other growth settings.

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“…that is simply too large to fit into one article. The interested reader should refer to other reviews of this and other compound semiconductor surfaces that have been previously published [6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%