Doctoral Dissertations
Abstract
"Ice crystal nucleation on 1 80 keV Si+ ion implanted silicon was investigated experimentally at three different temperatures: T = - 20 °, - 24 °, and -30 ° C. The ion doses ranged from 4 .0 x 1014 ions/cm2 to 5 .0 x 1015 ions/cm2. The supersaturation dependence of ice nucleation on the ion implanted samples at these three temperatures was observed by controlling the substrate temperature and relative humidity independently.
An enhanced ice nucleation activity was observed on samples implanted with ion doses in the range of (1.6 - 2.0) x 1015 ions/cm2. On these samples, the necessary supersaturation with respect to ice for the appearance of ice crystals is reduced 20% as compared to samples of lower or higher doses. The number of ice crystals nucleated in the implanted region of the samples with doses (1.6 - 2.0) x 1015 ions/cm2 is substantially more than in the unimplanted region of the same sample, for the same supersaturation.
The increased efficiency of the ion implanted samples is attributed to reduced water bonding to the silicon surface due to dehydroxylation of the surface by ion sputtering. In this model at low ion doses, the surface is hydrophilic due to already present chemisorbed hydroxyls. The incident Si+ ions sputter the hydroxyls from the surface, hydrophobing it and causing surface damage. The efficient samples of doses (1.6 - 2 .0) x 1015 ions/cm2 are surfaces which are essentially hydrophobic but contain a few remaining hydrophilic sites (pair hydroxyls) with little surface disorder. These results are in good agreement with the general view that an efficient and active ice nucleus is a surface which has hydrophobic but contains a few hydrophilic sit es (Hobbs, 1974)"-- Abstract, pp. ii-iii
Advisor(s)
Kassner, James L.
Committee Member(s)
Sparlin, Don M., 1937-2024
Hale, Barbara N., 1938-2024
Peacher, Jerry
Hatfield, Charles, 1920-1993
Department(s)
Physics
Degree Name
Ph. D. in Physics
Publisher
University of Missouri--Rolla
Publication Date
Spring 1982
Pagination
xiv, 103 pages
Note about bibliography
Includes bibliographical references (pages 84-93)
Rights
© 1982 William Henry Stinebaugh, All rights reserved.
Document Type
Dissertation - Open Access
File Type
text
Language
English
Thesis Number
T 4666
Print OCLC #
9233509
Recommended Citation
Stinebaugh, William Henry, "The heterogeneous nucleation of ice on ion implanted silicon" (1982). Doctoral Dissertations. 101.
https://scholarsmine.mst.edu/doctoral_dissertations/101
