Characterization Of Rare-Earth Monopnictide Nanoparticles Grown By Inert Gas Condensation
Date
2016-05
Authors
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Journal ISSN
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Publisher
University of Delaware
Abstract
The incorporation of rare earth monopnictide (RE-V) nanoparticles in III-V
semiconductor matrices has created a new class of materials called semiconductor
nanocomposites. These materials exhibit enhanced properties for thermoelectric and
terahertz radiation applications compared to conventional materials. A new method by
which these materials are grown has been proposed using the combined use of inert
gas condensation (IGC) and liquid phase epitaxy (LPE) in which nanoparticles are
produced by IGC and then grown into a semiconductor film with LPE. This new
method allows for scalability, fast growth rates, flexibility, and the ability to grow and
characterize the nanoparticles and films separately. However, the development of this
growth method is dependent on a fundamental understanding of both IGC and LPE
growth methods individually. Furthermore, the characterization of the nanoparticles
grown by IGC is necessary before they are inserted into the III-V semiconductor
matrix by LPE.
In this work, the investigation of various IGC growth parameters in RE-V
nanoparticle growths is investigated including laser fluence, inert gas pressure,
collection distance, and source composition. Furthermore, size characterization is
performed to understand the average size and size distribution of nanoparticles grown
by IGC. Size control of the nanoparticles is investigated. Lastly, preliminary work is
performed to develop a Scherrer correlation.
It was found that ErAs nanoparticle growths are benefitted from a laser fluence
higher than 0.9 J/cm2, He pressure higher than 30 torr, small collection distances
(~1.25 cm), and a source pellet composition of 4:1 Er:As (at %). No significant size
change occurred with varying growth parameters. The average ErAs nanoparticle size
was 5 nm +/- 2 nm. The shape factor (K) for the Scherrer correlation was determined
to be 0.124 but more work is required to determine the validity of this value across a
range of nanoparticle sizes.
Description
Keywords
inert gas condensation, nanoparticles, chemical engineering