Dynamics of film growth of GaAs by MBE from Rheed observations

Neave, J.H.; Joyce, B.A.; Dobson, Peter J.; Norton, Nicholas G.

doi:10.1007/bf00617180

Cited by 951 publications

(189 citation statements)

References 20 publications

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“…The amplitude of these oscillations is a sensitive measure of structural perfection in the surface region. While in this respect they are similar to intensity oscillations routinely observed by reflection high-energy electron diffraction during film growth by molecular-beam epitaxy, 21 the reflected x-ray intensity permits a kinematic analysis allowing a more detailed modeling of surface structure and morphology.…”

Section: Introductionsupporting

confidence: 62%

Synchrotron x-ray-diffraction study of the structure and growth of Xe films adsorbed on the Ag(111) surface

Dai

Angot

et al. 1999

Phys. Rev. B

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Synchrotron x-ray scattering has been used to investigate the structure and growth of perhaps the simplest of all films: xenon physisorbed on the Ag͑111͒ surface. High-resolution x-ray scans of the in-plane structure and lower-resolution scans ͑specular and nonspecular͒ of the out-of-plane order were performed. The Xe films were prepared under both quasiequilibrium and kinetic growth conditions, and have fewer structural defects than those investigated previously by others on graphite substrates. Under quasiequilibrium conditions, the bulk Xe-Xe spacing is reached at monolayer completion, and the monolayer and bilayer lattice constants at coexistence are inferred equal to within 0.005 Å, consistent with theoretical calculations. The Xe/vacuum interface profile for a complete monolayer and bilayer grown at quasiequilibrium is found to be sharper than for kinetically grown films. At coverages above two layers, diffraction scans along the Xe(01l) rod for quasiequilibrated films are consistent with the presence of two domains having predominantly an ABC stacking sequence and rotated 60°with respect to each other about the surface normal. Annealing of these films alters neither the population of the two domains nor the fraction of ABA stacking faults. The thickest film grown under quasiequilibrium conditions exceeds 220 Å ͑resolution limited͒. Under kinetic growth conditions, x-ray intensity oscillations at the Xe anti-Bragg position of the specular rod are observed as a function of time, indicating nearly layer-by-layer growth. Up to four complete oscillations corresponding to a film of eight layers have been observed before the intensity is damped out; the number of oscillations is found to depend on the substrate temperature, the growth rate, and the quality of the Ag͑111͒ substrate. The specular reflectivity from kinetically grown films at nominal coverages of three and four layers has been analyzed using a Gaussian model which gives a film thickness standard deviation of 0.5 and 1.0 layers, respectively. Diffraction scans along the Xe(01l) rod of these films indicate a larger fraction of ABA stacking faults than found for thicker films. These results demonstrate the difficulty of kinetically growing Xe films thicker than two layers which have an ideal slab geometry. ͓S0163-1829͑99͒03723-6͔

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Section: Introductionsupporting

confidence: 62%

Synchrotron x-ray-diffraction study of the structure and growth of Xe films adsorbed on the Ag(111) surface

Dai

Angot

et al. 1999

Phys. Rev. B

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“…13,14 The intensity of the specularly-reflected RHEED spot is commonly used, which oscillates depending on the step edge density of the film. One oscillation period corresponds to the deposition of one unit cell layer in the unit cell-by-unit cell growth.…”

Section: Resultsmentioning

confidence: 99%

Constructing oxide interfaces and heterostructures by atomic layer-by-layer laser molecular beam epitaxy

et al. 2017

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Advancements in nanoscale engineering of oxide interfaces and heterostructures have led to discoveries of emergent phenomena and new artificial materials. Combining the strengths of reactive molecular-beam epitaxy and pulsed-laser deposition, we show here, with examples of Sr 1+x Ti 1-x O 3+δ , Ruddlesden-Popper phase La n+1 Ni n O 3n+1 (n = 4), and LaAl 1+y O 3(1+0.5y) /SrTiO 3 interfaces, that atomic layer-by-layer laser molecular-beam epitaxy significantly advances the state of the art in constructing oxide materials with atomic layer precision and control over stoichiometry. With atomic layer-by-layer laser molecular-beam epitaxy we have produced conducting LaAlO 3 /SrTiO 3 interfaces at high oxygen pressures that show no evidence of oxygen vacancies, a capability not accessible by existing techniques. The carrier density of the interfacial two-dimensional electron gas thus obtained agrees quantitatively with the electronic reconstruction mechanism.npj Quantum Materials (2017) 2:10 ; doi:10.1038/s41535-017-0015-x INTRODUCTION Technological advances in atomic-layer control during oxide film growth have enabled the discoveries of new phenomena and new functional materials, such as the two-dimensional (2D) electron gas at the LaAlO 3 /SrTiO 3 interface, 1, 2 and asymmetric three-component ferroelectric superlattices. 3,4 Reactive molecular-beam epitaxy (MBE) and pulsed-laser deposition (PLD) are the two most successful growth techniques for epitaxial heterostructures of complex oxides. PLD possesses experimental simplicity, low cost, and versatility in the materials to be deposited. 5 Reactive MBE employing alternately-shuttered elemental sources (atomic layerby-layer MBE, or ALL-MBE) can control the cation stoichiometry precisely, thus producing oxide thin films of exceptional quality. [6][7][8] There are, however, limitations in both techniques. Reactive MBE can use only source elements whose vapor pressure is sufficiently high, excluding a large fraction of 4d and 5d metals. In addition, ozone is needed to create a highly oxidizing environment while maintaining low-pressure MBE conditions, which increases the system complexity. On the other hand, conventional PLD using a compound target often results in cation off-stoichiometry in the films. 9, 10 In this paper we present an approach that combines the strengths of reactive MBE and PLD: atomic layer-by-layer laser MBE (ALL-Laser MBE) using separate oxide targets. Ablating alternately the targets of constituent oxides, for example SrO and TiO 2 , a SrTiO 3 film can be grown one atomic layer at a time. Stoichiometry for both the cations and oxygen in the oxide films can be controlled. Although the idea of depositing atomic layers by PLD has been explored since the early days of laser MBE, 11,12 we show that levels of stoichiometry control and crystalline perfection rivaling those of

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“…In comparison, Figure 2a shows the same electron diffraction analysis for a CaO film prepared in an equivalent flux of water vapour. In this case, steady RHEED intensity oscillations are observed during the entire process, indicating 2D growth, and the final static RHEED image is streaky, indicating a smooth (though crystallographically imperfect) surface 17 . We note that the oscillation amplitude decays with time.…”

Section: Film Depositionmentioning

confidence: 88%

Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions

et al. 2011

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Property coupling at interfaces between active materials is a rich source of functionality, if defect densities are low, interfaces are smooth and the microstructure is featureless. Conventional synthesis techniques generally fail to achieve this when materials have highly dissimilar structure, symmetry and bond type-precisely when the potential for property engineering is most pronounced. Here we present a general synthesis methodology, involving systematic control of the chemical boundary conditions in situ, by which the crystal habit, and thus growth mode, can be actively engineered. In so doing, we establish the capability for layer-by-layer deposition in systems that otherwise default to island formation and grainy morphology. This technique is demonstrated via atomically smooth {111} calcium oxide films on (0001) gallium nitride. The operative surfactant-based mechanism is verified by temperature-dependent predictions from ab initio thermodynamic calculations. Calcium oxide films with smooth morphology exhibit a three order of magnitude enhancement of insulation resistance.

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Dynamics of film growth of GaAs by MBE from Rheed observations

Cited by 951 publications

References 20 publications

Synchrotron x-ray-diffraction study of the structure and growth of Xe films adsorbed on the Ag(111) surface

Synchrotron x-ray-diffraction study of the structure and growth of Xe films adsorbed on the Ag(111) surface

Constructing oxide interfaces and heterostructures by atomic layer-by-layer laser molecular beam epitaxy

Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions

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