Energy-dispersive X-ray reflectivity and GID for real-time growth studies of pentacene thin films

Kowarik, Stefan; Gerlach, Alexander; Leitenberger, W.; Hu, Jing; Witte, Gregor; Wöll, Christof; Pietsch, U.; Schreiber, Frank

doi:10.1016/j.tsf.2006.12.020

Cited by 58 publications

(53 citation statements)

References 25 publications

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“…One is to use a white x-ray beam and an energy dispersive detector. [9][10][11][12] However, the heat load on the sample due to the white beam is tremendous and samples can easily be damaged. Furthermore x-ray sources such as x-ray tubes and undulator sources cannot deliver high-intensity white beams with uniform energy distribution of the photons.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, the time resolution and q-resolution are strongly limited by the energy resolution and the dynamic range of the detector. [9][10][11][12] Another approach is to generate a strongly focused x-ray beam and to make use of the divergence of the beam for an angular dispersive reflectivity. 13 Here the q-space and resolution are restricted by the maximum opening angle of the focused beam.…”

Section: Introductionmentioning

confidence: 99%

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A new setup for high resolution fast X-ray reflectivity data acquisition

Buffet

Pflaum

Ehnes

et al. 2016

Review of Scientific Instruments

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A new method for fast x-ray reflectivity data acquisition is presented. The method is based on a fast rotating, slightly tilted sample reflecting to a stationary mounted position sensitive detector and it allows for measurements of reflectivity curves in a quarter of a second. The resolution in q-space mainly depends on the beam properties and the pixel size of the detector. Maximum q z -value of 1 Å −1 can be achieved. The time-temperature depending structure changes of poly(Nisopropylacrylamide) thin films were investigated in situ by applying the fast-reflectivity setup. The results are presented in this paper as illustration of the method and proof of principle. Published by AIP Publishing. [http://dx

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A new setup for high resolution fast X-ray reflectivity data acquisition

Buffet

Pflaum

Ehnes

et al. 2016

Review of Scientific Instruments

View full text Add to dashboard Cite

show abstract

“…An additional advantage of x-ray scattering is the accuracy with which precise calculations of scattered intensity can be performed. Increasingly, this has been exploited [13][14][15][16][17][18][19][20][21] to extract quantitative information about the surface morphology, namely the layer coverages as a function of time θ n (t), during growth. This analysis, however, requires a specific model of the morphological evolution of the film.…”

Section: Introductionmentioning

confidence: 99%

“…As has recently been demonstrated 15,17,18,22,23 , measuring multiple points along the reflectivity curve can reduce or potentially obviate the requirement for such models. However, such measurements are not always possible or compatible with a particular system or experiment.…”

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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“…For ex situ samples, XRR is a well established method used by a large community (Tolan, 1999). In situ XRR measurements were carried out using energy-dispersive reflectivity setups (Kowarik et al, 2007) or monochromatic radiation. In the latter case, in situ XRR measurements can be performed by scanning the angular range (Chiarello et al, 1997) or measuring at a fixed angular position (Louis et al, 1994;Peverini et al, 2005;Lee et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Monitoring the thin film formation during sputter deposition of vanadium carbide

Kaufholz

Krause

Kotapati

et al. 2015

J Synchrotron Radiat

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The thin film formation of magnetron sputtered polycrystalline coatings was monitored by in situ X-ray reflectivity measurements. The measured intensity was analyzed using the Parratt algorithm for time-dependent thin film systems. Guidelines for the on-line interpretation of the data were developed. For thick coatings, the experimental resolution needs to be included in the data evaluation in order to avoid misinterpretations. Based on a simple layer model, the timedependent mean electron density, roughness and growth velocity were extracted from the data. As an example, the method was applied to the hard coating material vanadium carbide. Both instantaneous and slowly varying changes of the coating could be detected. It was shown that the growth velocity is proportional to the DC power. Significant changes of the microstructure induced by the working gas pressure are mainly driven by the chemical composition.

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Energy-dispersive X-ray reflectivity and GID for real-time growth studies of pentacene thin films

Cited by 58 publications

References 25 publications

A new setup for high resolution fast X-ray reflectivity data acquisition

A new setup for high resolution fast X-ray reflectivity data acquisition

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

Monitoring the thin film formation during sputter deposition of vanadium carbide

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