skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Study of surface cleaning methods and pyrolysis temperatures on nanostructured carbon films using x-ray photoelectron spectroscopy

Abstract

Nanostructured carbon (ns-C) films fabricated by stabilization and pyrolysis of diblock copolymers are of interest for a variety of electrical/electronic applications due to their chemical inertness, high-temperature insensitivity, very high surface area, and tunable electrical resistivity over a wide range [Kulkarni et al., Synth. Met. 159, 177 (2009)]. Because of their high porosity and associated high specific surface area, controlled surface cleaning studies are important for fabricating electronic devices from these films. In this study, quantification of surface composition and surface cleaning studies on ns-C films synthesized by carbonization of diblock copolymers of polyacrylonitrile-b-poly(n-butyl acrylate) at two different temperatures were carried out. X-ray photoelectron spectroscopy was used for elemental analysis and to determine the efficacy of various surface cleaning methods for ns-C films and to examine the polymer residues in the films. The in-situ surface cleaning methods included HF vapor treatment, vacuum annealing, and exposure to UV-ozone. Quantitative analysis of high-resolution XPS scans showed 11 at. % nitrogen was present in the films pyrolyzed at 600 Degree-Sign C, suggesting incomplete denitrogenation of the copolymer films. The nitrogen atomic concentration decreased significantly for films pyrolyzed at 900 Degree-Sign C confirming extensive denitrogenation at that temperature. Furthermore, quantitative analysis of nitrogen subpeaksmore » indicated higher loss of nitrogen atoms residing at the edge of graphitic clusters relative to that of nitrogen atoms within the graphitic clusters, suggesting higher graphitization with increasing pyrolysis temperature. Of the surface cleaning methods investigated, in-situ annealing of the films at 300 Degree-Sign C for 40 min was found to be the most efficacious in removing adventitious carbon and oxygen impurities from the surface.« less

Authors:
; ; ; ; ;  [1];  [2];  [2]
  1. Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
22102196
Resource Type:
Journal Article
Journal Name:
Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films
Additional Journal Information:
Journal Volume: 30; Journal Issue: 6; Other Information: (c) 2012 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0734-2101
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ACRYLATES; ANNEALING; CARBONIZATION; COPOLYMERS; ELECTRIC CONDUCTIVITY; ELECTRONIC EQUIPMENT; GRAPHITE; HYDROFLUORIC ACID; NANOSTRUCTURES; NITRILES; NITROGEN; OXYGEN; PYROLYSIS; RESOLUTION; SPECIFIC SURFACE AREA; SURFACE AREA; SURFACE CLEANING; THIN FILMS; ULTRAVIOLET RADIATION; X-RAY PHOTOELECTRON SPECTROSCOPY

Citation Formats

Kerber, Pranita, Porter, Lisa M., McCullough, Lynne A., Kowalewski, Tomasz, Engelhard, Mark, Baer, Donald, Chemistry Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352. Study of surface cleaning methods and pyrolysis temperatures on nanostructured carbon films using x-ray photoelectron spectroscopy. United States: N. p., 2012. Web. doi:10.1116/1.4759238.
Kerber, Pranita, Porter, Lisa M., McCullough, Lynne A., Kowalewski, Tomasz, Engelhard, Mark, Baer, Donald, Chemistry Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, & Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352. Study of surface cleaning methods and pyrolysis temperatures on nanostructured carbon films using x-ray photoelectron spectroscopy. United States. doi:10.1116/1.4759238.
Kerber, Pranita, Porter, Lisa M., McCullough, Lynne A., Kowalewski, Tomasz, Engelhard, Mark, Baer, Donald, Chemistry Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352. Thu . "Study of surface cleaning methods and pyrolysis temperatures on nanostructured carbon films using x-ray photoelectron spectroscopy". United States. doi:10.1116/1.4759238.
@article{osti_22102196,
title = {Study of surface cleaning methods and pyrolysis temperatures on nanostructured carbon films using x-ray photoelectron spectroscopy},
author = {Kerber, Pranita and Porter, Lisa M. and McCullough, Lynne A. and Kowalewski, Tomasz and Engelhard, Mark and Baer, Donald and Chemistry Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352},
abstractNote = {Nanostructured carbon (ns-C) films fabricated by stabilization and pyrolysis of diblock copolymers are of interest for a variety of electrical/electronic applications due to their chemical inertness, high-temperature insensitivity, very high surface area, and tunable electrical resistivity over a wide range [Kulkarni et al., Synth. Met. 159, 177 (2009)]. Because of their high porosity and associated high specific surface area, controlled surface cleaning studies are important for fabricating electronic devices from these films. In this study, quantification of surface composition and surface cleaning studies on ns-C films synthesized by carbonization of diblock copolymers of polyacrylonitrile-b-poly(n-butyl acrylate) at two different temperatures were carried out. X-ray photoelectron spectroscopy was used for elemental analysis and to determine the efficacy of various surface cleaning methods for ns-C films and to examine the polymer residues in the films. The in-situ surface cleaning methods included HF vapor treatment, vacuum annealing, and exposure to UV-ozone. Quantitative analysis of high-resolution XPS scans showed 11 at. % nitrogen was present in the films pyrolyzed at 600 Degree-Sign C, suggesting incomplete denitrogenation of the copolymer films. The nitrogen atomic concentration decreased significantly for films pyrolyzed at 900 Degree-Sign C confirming extensive denitrogenation at that temperature. Furthermore, quantitative analysis of nitrogen subpeaks indicated higher loss of nitrogen atoms residing at the edge of graphitic clusters relative to that of nitrogen atoms within the graphitic clusters, suggesting higher graphitization with increasing pyrolysis temperature. Of the surface cleaning methods investigated, in-situ annealing of the films at 300 Degree-Sign C for 40 min was found to be the most efficacious in removing adventitious carbon and oxygen impurities from the surface.},
doi = {10.1116/1.4759238},
journal = {Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films},
issn = {0734-2101},
number = 6,
volume = 30,
place = {United States},
year = {2012},
month = {11}
}