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Title: Growth dynamics of pentacene thin films: Real-time synchrotron x-ray scattering study

Abstract

Real-time synchrotron x-ray scattering in the anti-Bragg configuration was used to monitor the dynamics of pentacene film growth on inert substrates. A distributed-growth model, according to which pentacene molecules adsorbed on the nth layer can either nucleate and contribute to the growth of the (n+1)th layer or transfer downward and contribute to the growth of the nth layer, gave a good description of the data. For molecules adsorbed on the first and second layers, the probability of downward transfer was found to be dependent on the substrate, and independent of temperature within the range from 25 to 60 deg. C. For films grown on SiO{sub 2}, an Ehrlich-Schwoebel barrier of the order of 70 meV dominated downward transfer of pentacene molecules in layers away from the substrate. For films grown on an alkylated self-assembled monolayer, significant desorption of pentacene molecules from the substrate at elevated temperatures forced the growth mode toward the three-dimensional limit.

Authors:
; ;  [1]; ;  [2];  [3]
  1. Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States)
  2. Department of Physics, University of Vermont, Burlington, Vermont 05405 (United States)
  3. Cornell High Energy Synchrotron Source, Ithaca, New York 14853 (United States)
Publication Date:
OSTI Identifier:
20788191
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 73; Journal Issue: 20; Other Information: DOI: 10.1103/PhysRevB.73.205307; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTAL GROWTH; DESORPTION; LAYERS; MOLECULES; ORGANIC SEMICONDUCTORS; PENTACENE; PROBABILITY; SILICON OXIDES; SUBSTRATES; THIN FILMS; X-RAY DIFFRACTION

Citation Formats

Mayer, Alex C., Ruiz, Ricardo, Malliaras, George G., Zhou, Hua, Headrick, Randall L., and Kazimirov, Alexander. Growth dynamics of pentacene thin films: Real-time synchrotron x-ray scattering study. United States: N. p., 2006. Web. doi:10.1103/PHYSREVB.73.2.
Mayer, Alex C., Ruiz, Ricardo, Malliaras, George G., Zhou, Hua, Headrick, Randall L., & Kazimirov, Alexander. Growth dynamics of pentacene thin films: Real-time synchrotron x-ray scattering study. United States. doi:10.1103/PHYSREVB.73.2.
Mayer, Alex C., Ruiz, Ricardo, Malliaras, George G., Zhou, Hua, Headrick, Randall L., and Kazimirov, Alexander. Mon . "Growth dynamics of pentacene thin films: Real-time synchrotron x-ray scattering study". United States. doi:10.1103/PHYSREVB.73.2.
@article{osti_20788191,
title = {Growth dynamics of pentacene thin films: Real-time synchrotron x-ray scattering study},
author = {Mayer, Alex C. and Ruiz, Ricardo and Malliaras, George G. and Zhou, Hua and Headrick, Randall L. and Kazimirov, Alexander},
abstractNote = {Real-time synchrotron x-ray scattering in the anti-Bragg configuration was used to monitor the dynamics of pentacene film growth on inert substrates. A distributed-growth model, according to which pentacene molecules adsorbed on the nth layer can either nucleate and contribute to the growth of the (n+1)th layer or transfer downward and contribute to the growth of the nth layer, gave a good description of the data. For molecules adsorbed on the first and second layers, the probability of downward transfer was found to be dependent on the substrate, and independent of temperature within the range from 25 to 60 deg. C. For films grown on SiO{sub 2}, an Ehrlich-Schwoebel barrier of the order of 70 meV dominated downward transfer of pentacene molecules in layers away from the substrate. For films grown on an alkylated self-assembled monolayer, significant desorption of pentacene molecules from the substrate at elevated temperatures forced the growth mode toward the three-dimensional limit.},
doi = {10.1103/PHYSREVB.73.2},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 20,
volume = 73,
place = {United States},
year = {Mon May 15 00:00:00 EDT 2006},
month = {Mon May 15 00:00:00 EDT 2006}
}
  • The temporal evolution of high quality indium nitride (InN) growth by plasma-assisted atomic layer epitaxy (ALEp) on a-plane sapphire at 200 and 248 °C was probed by synchrotron x-ray methods. The growth was carried out in a thin film growth facility installed at beamline X21 of the National Synchrotron Light Source at Brookhaven National Laboratory and at beamline G3 of the Cornell High Energy Synchrotron Source, Cornell University. Measurements of grazing incidence small angle x-ray scattering (GISAXS) during the initial cycles of growth revealed a broadening and scattering near the diffuse specular rod and the development of scattering intensities duemore » to half unit cell thick nucleation islands in the Yoneda wing with correlation length scale of 7.1 and 8.2 nm, at growth temperatures (Tg) of 200 and 248 °C, respectively. At about 1.1 nm (two unit cells) of growth thickness nucleation islands coarsen, grow, and the intensity of correlated scattering peak increased at the correlation length scale of 8.0 and 8.7 nm for Tg = 200 and 248 °C, respectively. The correlated peaks at both growth temperatures can be fitted with a single peak Lorentzian function, which support single mode growth. Post-growth in situ x-ray reflectivity measurements indicate a growth rate of ~0.36 Å/cycle consistent with the growth rate previously reported for self-limited InN growth in a commercial ALEp reactor. Consistent with the in situ GISAXS study, ex situ atomic force microscopy power spectral density measurements also indicate single mode growth. Electrical characterization of the resulting film revealed an electron mobility of 50 cm2/V s for a 5.6 nm thick InN film on a-plane sapphire, which is higher than the previously reported mobility of much thicker InN films grown at higher temperature by molecular beam epitaxy directly on sapphire. These early results indicated that in situ synchrotron x-ray study of the epitaxial growth kinetics of InN films is a very powerful method to understand nucleation and growth mechanisms of ALEp to enable improvement in material quality and broaden its application.« less
  • No abstract prepared.
  • No abstract prepared.