Bomphrey, John James (2011) Growth and characterisation of dilute nitride antimonide layers by plasma-assisted molecular beam epitaxy. PhD thesis, University of Warwick.

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Abstract

The work presented in this thesis is concerned with the growth and characterisation
of III-NSb films by plasma-assisted molecular beam epitaxy (PA-MBE). The
research was motivated by their application in technologically important regions of
the IR spectrum.
Homoepitaxial growth of GaSb films was conducted and characterised as a function
of V:III ratio and growth temperature, permitting observation of morphology
changes with growth conditions, also providing insight into surfaces of the ternary
dilute nitride. Heteroepitaxial GaSb/GaAs growth has highlighted defect formation
and propagation arising from lattice mismatched deposition.
Films of GaNxSb1-x, a material of interest for device applications in the 2-5 μm
spectral range, have been grown on GaSb(001) substrates. The results demonstrate
the degree to which substitutional N content may be controlled through variation of
the temperature and rate of deposition. Models based upon kinetic and
thermodynamic principles and previously applied to GaNxAs1-x have been evaluated
for N content of GaNxSb1-x films as a function of the rate and temperature used for
growth.
The growth of InNxSb1-x, an alloy of significance in the technologically important
wavelength region of 8-12 μm, upon InSb(001) substrates is described. There is
qualitative agreement with the temperature dependence of N content. Analysis of
the substitutional N content as a function of growth rate, however, suggests a
difference between GaNxSb1-x and GaNxAs1-x. An explanation is presented for the
trend in the level of substitutional N uptake across III-V-N materials.
Further experiments are proposed to extend the parameter space sampled in the
investigation of GaNxSb1-x and InNxSb1-x films, with regard to the Sb:III ratio
employed during growth. Initial results are reported from measurements undertaken
with a pyrometer operating at 1.6 μm, suggesting that growth can be conducted at
lower temperatures. Additional preliminary results are presented for the growth of
GaxIn1-xNySb1-y films, demonstrating a tuneable band gap quaternary material, lattice
matched to GaSb is possible.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Molecular beam epitaxy, Homoepitaxy, Thin films
Official Date:	May 2011
Dates:	Date Event May 2011 Submitted
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Jones, Tim
Extent:	xii, 254 leaves : ill., charts
Language:	eng

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