Angular distributions and total yields of atoms sputtered from bismuth targets by normally incident 10 keV -50 keV Ne+ and Ar+ ions have been measured both experimentally and by computer simulation. Polycrystalline Bi targets were used for experimental measurements. The sputtered atoms were collected on high purity aluminum foils under ultra-high vacuum conditions, and were subsequently analyzed using Rutherford backscattering spectroscopy. The Monte-Carlo based SRIM code was employed to simulate angular distributions of sputtered Bi atoms and total sputtering yields of Bi to compare with experiment. The measured sputtering yields were found to increase with increasing projectile energy for normally incident 10 keV - 50 keV Ne+ and Ar+ ions. The shapes of the angular distributions of sputtered Bi atoms demonstrated good agreement between experiment and simulation in the present study. The measured and simulated angular distributions of sputtered Bi exhibited an over-cosine tendency. The measured value of the degree of this over-cosine nature was observed to increase with increasing incident Ne+ ion energy, but was not strongly dependent on incident Ar+ ion energy. The differential angular sputtering yield and partial sputtering yields due to Ar ion bombardment of an inhomogeneous liquid Bi:Ga alloy have been investigated, both experimentally and by computer simulation. Normally incident 25 keV and 50 keV beams of Ar+ were used to sputter a target of 99.8 at% Ga and 0.2 at% Bi held at 40° C in ultra-high vacuum (UHV), under which conditions the alloy is known to exhibit extreme Gibbsian surface segregation that produces essentially a monolayer of Bi atop the bulk liquid. Angular distributions of sputtered neutrals and partial sputtering yields obtained from the conversion of areal densities of Bi and Ga atoms on collector foils were determined. The Monte-Carlo based SRIM code was employed to simulate the experiment and obtain the angular distribution of sputtered components. The angular distribution of sputtered Ga atoms, originating from underneath the surface monolayer, was measured to be sharply peaked in angle about the surface normal direction compared to the Bi atoms originating from surface monolayer. The simulation study produced contradicting results, where the species originating from surface monolayer was strongly peaked around the surface normal compared to the species originating from beneath the surface monolayer.
| Identifer | oai:union.ndltd.org:unt.edu/info:ark/67531/metadc700021 |
| Date | 12 1900 |
| Creators | Deoli, Naresh T. |
| Contributors | Weathers, Duncan L., Matteson, Samuel L., Rout, Bibhudutta, McDaniel, Floyd Del. (Floyd Delbert), 1942- |
| Publisher | University of North Texas |
| Source Sets | University of North Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Format | ix, 88 pages : illustrations (some color), Text |
| Rights | Public, Deoli, Naresh T., Copyright, Copyright is held by the author, unless otherwise noted. All rights reserved. |
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