Multiple Time Scales in Diffraction Measurements of Diffusive Surface Relaxation

Fleet, Aaron; Dale, Darren; Woll, Arthur R.; Suzuki, Yuri; Brock, J. D.

doi:10.1103/physrevlett.96.055508

Cited by 34 publications

(25 citation statements)

References 27 publications

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“…Hence, we attribute a nearly constant τ to thermal growth. We note that there can be multiple relaxation times present in the RHEED intensity recovery, 24 and fits of the specular RHEED intensity using two time constants gave consistent results. In order to quantify the observed difference, we use e = σ/τ ̅ , where σ is the standard deviation of τ and τ ̅ is the average of τ. e is thus a measure of the relative variation of the adatom relaxation times.…”

supporting

confidence: 65%

Consequences of High Adatom Energy during Pulsed Laser Deposition of La_0.7Sr_0.3MnO₃

Boschker

Folven

Monsen

et al. 2012

Crystal Growth & Design

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The impact of the adatom energy on the stoichiometry, surface morphology, and crystalline twinning during pulsed laser deposition of La 0.7 Sr 0.3 MnO 3 is studied. We show that although nonthermal growth using highly energetic adatoms results in very smooth ultrathin films, it also causes preferential resputtering of Mn and a surface roughening transition with increasing film thickness. This can be circumvented by carefully tuning the adatom energy into thermal growth, resulting in more Mn rich samples and a delayed roughening transition. Furthermore, we demonstrate that the crystalline twinning can be controlled by controlling the adatom energy. Hence, a detailed control of the adatom energy during growth opens for better stoichiometry control as well as surface quality.

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supporting

confidence: 65%

Consequences of High Adatom Energy during Pulsed Laser Deposition of La_0.7Sr_0.3MnO₃

Boschker

Folven

Monsen

et al. 2012

Crystal Growth & Design

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“…In situ, surface-sensitive scattering techniques, such as reflection high energy electron diffraction (RHEED) and x-ray scattering at the so-called "anti-Bragg" position [1][2][3] , yield direct information about surface morphology during growth, and have been applied to virtually all methods of thin film growth-such as electrodeposition 4 , molecular beam epitaxy (MBE), chemical vapor deposition (CVD) 5,6 , and pulsed laser deposition (PLD) [7][8][9][10][11][12] . Their principal advantages, compared to scan-probe microscopies such as atomic force microscopy (AFM), are their time resolution and the ease with which they can be incorporated into growth systems as qualitative, in situ probes.…”

Section: Introductionmentioning

confidence: 99%

Quantitative modeling ofin situx-ray reflectivity during organic molecule thin film growth

2011

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Synchrotron-based x-ray reflectivity is increasingly employed as an in situ probe of surface morphology during thin film growth, but complete interpretation of the results requires modeling the growth process. Many models have been developed and employed for this purpose, yet no detailed, comparative studies of their scope and accuracy exists in the literature. Using experimental data obtained from hyperthermal deposition of pentane and diindenoperylene (DIP) on SiO2, we compare and contrast three such models, both with each other and with detailed characterization of the surface morphology using ex-situ atomic force microscopy (AFM). These two systems each exhibit particular phenomena of broader interest: pentacene/SiO2 exhibits a rapid transition from rough to smooth growth. DIP/SiO2, under the conditions employed here, exhibits growth rate acceleration due to a different sticking probability between the substrate and film. In general, independent of which model is used, we find good agreement between the surface morphology obtained from fits to the in situx-ray data with the actual morphology at early times. This agreement deteriorates at later time, once the root-mean squared (rms) film roughness exceeds about 1 ML. A second observation is that, because layer coverages are under-determined by the evolution of a single point on the reflectivity curve, we find that the best fits to reflectivity data -corresponding to the lowest values of χ 2 ν -do not necessarily yield the best agreement between simulated and measured surface morphologies. Instead, it appears critical that the model reproduce all local extrema in the data. In addition to showing that layer morphologies can be extracted from a minimal set of data, the methodology established here provides a basis for improving models of multilayer growth by comparison to real systems.

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“…The first of these experiments was performed by a group from Oak Ridge at the Advanced Photon Source [14,15], investigating 〈001〉 SrTiO 3 homoepitaxy. Around the same time, our group was building and commissioning a new PLD/thin film growth laboratory and beamline at the Cornell High Energy Synchrotron Source (CHESS), where we have studied homoepitaxy and heteroepitaxy [16][17][18][19]. A group from the Paul Scherrer Institute has developed a PLD experiment at the Swiss Light Source and recently reported results on the growth of colossal magnetoresistance materials [20,21].…”

Section: Technical Reportsmentioning

confidence: 97%

Technical Report:In-situStudies of Pulsed Laser Deposition Growth at CHESS

Dale

Fleet

Woll

et al. 2007

Synchrotron Radiation News

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Recent advances in thin-film growth using advanced in-situ monitoring techniques have enabled materials engineering with atomic precision via the carefully controlled deposition of sequences of single atomic layers [1][2][3][4]. Epitaxial oxide heterostructures are especially attractive due to the broad range of materials properties that are manifest with changes in stoichiometry, even within a single structure family. Researchers are beginning to search for new phenomena that occur when these dissimilar materials are joined at atomically smooth interfaces [5][6][7][8].By combining in-situ time-resolved studies of film growth with exsitu techniques such as atomic-scale electron energy loss spectroscopy, and theoretical approaches such as molecular dynamics simulations and multi-scale modeling, we seek to understand the mechanisms operating during nucleation and growth, and the pathways by which materials engineering at the atomic scale can be realized.Pulsed Laser Deposition (PLD) is a very attractive case to study for a number of reasons. Over the last two decades, PLD has been established as the research and development technique of choice for producing high quality, thin, epitaxial films of complex oxide materials. The strength of the Figure 1: A 100 MW/cm 2 , 248 nm, KrF excimer laser, 30 ns in duration, ablates material from a polycrystalline target, creating a hot plume of energetic neutrals, ions, and clusters. The plume expands, cools, and condenses on the opposing single crystal substrate, which is generally heated to temperatures between 500°C and 800°C. During growth, 10 KeV X-rays generated by the Cornell High Energy Synchrotron Source (CHESS) are directed at the single crystal substrate. The intensity of scattered X-rays is monitored as a function of time, yielding information about film thickness, surface roughness, and growth mode. Figure 2: A photograph of the in-situ PLD equipment. The growth chamber is an integral part of the diffractometer, yet can be easily removed to make room for studies of alternative growth techniques. The pulsed laser beam path is illustrated in purple, and the X-ray beam path in green.

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Multiple Time Scales in Diffraction Measurements of Diffusive Surface Relaxation

Cited by 34 publications

References 27 publications

Consequences of High Adatom Energy during Pulsed Laser Deposition of La_0.7Sr_0.3MnO₃

Consequences of High Adatom Energy during Pulsed Laser Deposition of La_0.7Sr_0.3MnO₃

Quantitative modeling ofin situx-ray reflectivity during organic molecule thin film growth

Technical Report:In-situStudies of Pulsed Laser Deposition Growth at CHESS

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Multiple Time Scales in Diffraction Measurements of Diffusive Surface Relaxation

Cited by 34 publications

References 27 publications

Consequences of High Adatom Energy during Pulsed Laser Deposition of La0.7Sr0.3MnO3

Consequences of High Adatom Energy during Pulsed Laser Deposition of La0.7Sr0.3MnO3

Quantitative modeling ofin situx-ray reflectivity during organic molecule thin film growth

Technical Report:In-situStudies of Pulsed Laser Deposition Growth at CHESS

Contact Info

Product

Resources

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Consequences of High Adatom Energy during Pulsed Laser Deposition of La_0.7Sr_0.3MnO₃

Consequences of High Adatom Energy during Pulsed Laser Deposition of La_0.7Sr_0.3MnO₃