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Title: Adsorption calorimetry during metal vapor deposition on single crystal surfaces: Increased flux, reduced optical radiation, and real-time flux and reflectivity measurements

Abstract

Thin films of metals and other materials are often grown by physical vapor deposition. To understand such processes, it is desirable to measure the adsorption energy of the deposited species as the film grows, especially when grown on single crystal substrates where the structure of the adsorbed species, evolving interface, and thin film are more homogeneous and well-defined in structure. Our group previously described in this journal an adsorption calorimeter capable of such measurements on single-crystal surfaces under the clean conditions of ultrahigh vacuum [J. T. Stuckless, N. A. Frei, and C. T. Campbell, Rev. Sci. Instrum. 69, 2427 (1998)]. Here we describe several improvements to that original design that allow for heat measurements with ∼18-fold smaller standard deviation, greater absolute accuracy in energy calibration, and, most importantly, measurements of the adsorption of lower vapor-pressure materials which would have previously been impossible. These improvements are accomplished by: (1) using an electron beam evaporator instead of a Knudsen cell to generate the metal vapor at the source of the pulsed atomic beam, (2) changing the atomic beam design to decrease the relative amount of optical radiation that accompanies evaporation, (3) adding an off-axis quartz crystal microbalance for real-time measurement of themore » flux of the atomic beam during calorimetry experiments, and (4) adding capabilities for in situ relative diffuse optical reflectivity determinations (necessary for heat signal calibration). These improvements are not limited to adsorption calorimetry during metal deposition, but also could be applied to better study film growth of other elements and even molecular adsorbates.« less

Authors:
; ; ; ;  [1]
  1. Department of Chemistry, Box 351700, University of Washington, Seattle, Washington 98195-1700 (United States)
Publication Date:
OSTI Identifier:
22251318
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 84; Journal Issue: 12; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ACCURACY; ADSORPTION; ATOMIC BEAMS; CALIBRATION; CALORIMETERS; CALORIMETRY; ELECTRON BEAMS; MICROBALANCES; MONOCRYSTALS; PHYSICAL VAPOR DEPOSITION; QUARTZ; REFLECTIVITY; THIN FILMS; TIME MEASUREMENT

Citation Formats

Sellers, Jason R. V., James, Trevor E., Hemmingson, Stephanie L., Farmer, Jason A., and Campbell, Charles T., E-mail: campbell@chem.washington.edu. Adsorption calorimetry during metal vapor deposition on single crystal surfaces: Increased flux, reduced optical radiation, and real-time flux and reflectivity measurements. United States: N. p., 2013. Web. doi:10.1063/1.4832980.
Sellers, Jason R. V., James, Trevor E., Hemmingson, Stephanie L., Farmer, Jason A., & Campbell, Charles T., E-mail: campbell@chem.washington.edu. Adsorption calorimetry during metal vapor deposition on single crystal surfaces: Increased flux, reduced optical radiation, and real-time flux and reflectivity measurements. United States. doi:10.1063/1.4832980.
Sellers, Jason R. V., James, Trevor E., Hemmingson, Stephanie L., Farmer, Jason A., and Campbell, Charles T., E-mail: campbell@chem.washington.edu. 2013. "Adsorption calorimetry during metal vapor deposition on single crystal surfaces: Increased flux, reduced optical radiation, and real-time flux and reflectivity measurements". United States. doi:10.1063/1.4832980.
@article{osti_22251318,
title = {Adsorption calorimetry during metal vapor deposition on single crystal surfaces: Increased flux, reduced optical radiation, and real-time flux and reflectivity measurements},
author = {Sellers, Jason R. V. and James, Trevor E. and Hemmingson, Stephanie L. and Farmer, Jason A. and Campbell, Charles T., E-mail: campbell@chem.washington.edu},
abstractNote = {Thin films of metals and other materials are often grown by physical vapor deposition. To understand such processes, it is desirable to measure the adsorption energy of the deposited species as the film grows, especially when grown on single crystal substrates where the structure of the adsorbed species, evolving interface, and thin film are more homogeneous and well-defined in structure. Our group previously described in this journal an adsorption calorimeter capable of such measurements on single-crystal surfaces under the clean conditions of ultrahigh vacuum [J. T. Stuckless, N. A. Frei, and C. T. Campbell, Rev. Sci. Instrum. 69, 2427 (1998)]. Here we describe several improvements to that original design that allow for heat measurements with ∼18-fold smaller standard deviation, greater absolute accuracy in energy calibration, and, most importantly, measurements of the adsorption of lower vapor-pressure materials which would have previously been impossible. These improvements are accomplished by: (1) using an electron beam evaporator instead of a Knudsen cell to generate the metal vapor at the source of the pulsed atomic beam, (2) changing the atomic beam design to decrease the relative amount of optical radiation that accompanies evaporation, (3) adding an off-axis quartz crystal microbalance for real-time measurement of the flux of the atomic beam during calorimetry experiments, and (4) adding capabilities for in situ relative diffuse optical reflectivity determinations (necessary for heat signal calibration). These improvements are not limited to adsorption calorimetry during metal deposition, but also could be applied to better study film growth of other elements and even molecular adsorbates.},
doi = {10.1063/1.4832980},
journal = {Review of Scientific Instruments},
number = 12,
volume = 84,
place = {United States},
year = 2013,
month =
}
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