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Median Implantation Depth and Implantation Profile of 3-18 keV Positrons in Amorphous Polymers.

Algers, John LU ; Sperr, P; Egger, W; Kogel, G and Maurer, Frans LU (2003) In Physical Review B 67(12). p.1-125404
Abstract
Most applications of positron beams require knowledge of the implantation characteristics for an appropriate interpretation of the experimental data. In this work, the median implantation depth as a function of implantation energy, z1/2(E), of 3–18 keV positrons and their implantation profile P(z,E) in a total of 13 thin films of atactic polystyrene, poly(styrene-co-acrylonitrile), and polymethylmethacrylate spin coated onto a silicon substrate were determined from positron lifetime measurements using a pulsed, low-energy positron beam. z1/2(E) and P(z,E) were determined from the measurement of the ortho-positronium yield obtained from the intensity I3 of the long lifetime. z1/2(E) was parametrized with the commonly used power-law fit... (More)
Most applications of positron beams require knowledge of the implantation characteristics for an appropriate interpretation of the experimental data. In this work, the median implantation depth as a function of implantation energy, z1/2(E), of 3–18 keV positrons and their implantation profile P(z,E) in a total of 13 thin films of atactic polystyrene, poly(styrene-co-acrylonitrile), and polymethylmethacrylate spin coated onto a silicon substrate were determined from positron lifetime measurements using a pulsed, low-energy positron beam. z1/2(E) and P(z,E) were determined from the measurement of the ortho-positronium yield obtained from the intensity I3 of the long lifetime. z1/2(E) was parametrized with the commonly used power-law fit z1/2(E) = (A/)En, with and E in units of g cm–3 and keV, respectively, yielding A = 2.81(±0.2) µg cm–2 and n = 1.71(±0.05). Excellent agreement between amorphous polymer and literature data on Al and Cu suggests that the median implantation depth of positrons for low- to medium-Z materials in the studied energy range is independent of structure and only a function of mass density. Fitting of the Makhovian implantation profile to the experimental data suggested that the value of the parameter m varies between 1.7 and 2.3, systematically increasing with z at constant implantation energy, but is independent of the implantation energy. Using an equation proposed by Baker et al., the experimental data of 12 of the 13 studied polymer films could be described with a slightly better agreement than the Makhovian equation. ©2003 The American Physical Society (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B
volume
67
issue
12
pages
1 - 125404
publisher
American Physical Society
external identifiers
  • wos:000182158000087
  • scopus:0037880589
ISSN
1550-235X
DOI
10.1103/PhysRevB.67.125404
language
English
LU publication?
yes
id
8350ce4b-9245-4485-8659-586c8db71fd7 (old id 129505)
date added to LUP
2007-07-12 14:43:14
date last changed
2018-02-18 04:23:52
@article{8350ce4b-9245-4485-8659-586c8db71fd7,
  abstract     = {Most applications of positron beams require knowledge of the implantation characteristics for an appropriate interpretation of the experimental data. In this work, the median implantation depth as a function of implantation energy, z1/2(E), of 3–18 keV positrons and their implantation profile P(z,E) in a total of 13 thin films of atactic polystyrene, poly(styrene-co-acrylonitrile), and polymethylmethacrylate spin coated onto a silicon substrate were determined from positron lifetime measurements using a pulsed, low-energy positron beam. z1/2(E) and P(z,E) were determined from the measurement of the ortho-positronium yield obtained from the intensity I3 of the long lifetime. z1/2(E) was parametrized with the commonly used power-law fit z1/2(E) = (A/)En, with and E in units of g cm–3 and keV, respectively, yielding A = 2.81(±0.2) µg cm–2 and n = 1.71(±0.05). Excellent agreement between amorphous polymer and literature data on Al and Cu suggests that the median implantation depth of positrons for low- to medium-Z materials in the studied energy range is independent of structure and only a function of mass density. Fitting of the Makhovian implantation profile to the experimental data suggested that the value of the parameter m varies between 1.7 and 2.3, systematically increasing with z at constant implantation energy, but is independent of the implantation energy. Using an equation proposed by Baker et al., the experimental data of 12 of the 13 studied polymer films could be described with a slightly better agreement than the Makhovian equation. ©2003 The American Physical Society},
  author       = {Algers, John and Sperr, P and Egger, W and Kogel, G and Maurer, Frans},
  issn         = {1550-235X},
  language     = {eng},
  number       = {12},
  pages        = {1--125404},
  publisher    = {American Physical Society},
  series       = {Physical Review B},
  title        = {Median Implantation Depth and Implantation Profile of 3-18 keV Positrons in Amorphous Polymers.},
  url          = {http://dx.doi.org/10.1103/PhysRevB.67.125404},
  volume       = {67},
  year         = {2003},
}