Precursors for doped boron carbide thin films

Guest, A

Abstract

This Thesis is concerned with the development of high yield synthetic strategies to
phosphaboranes and phosphacarboranes. These compounds have attracted attention
due to their potential as single-source precursors for the deposition of thin films of
doped boron carbide via plasma enhanced chemical vapour deposition. It has shown
that suitable doping of the boron carbide can lead to wide band gap semiconductors
and incorporation of phosphorus into the cage structure of the solid-state material is
one way of achieving this aim.
Chapter one discusses the chemical vapour deposition of boron carbide and goes on to
describe its uses as neutron detectors and semiconductors. Chapter two presents the
existing methods used for the synthesis of aminophosphines and highlights the
importance of two such species, PH(NBus2 )2 and PCl2N(CJln)2 .
The remaining chapters cover the experimental work used for the preparation of
phosphaboranes and phosphacarboranes that contain the phosphorus atom as a vertex.
Chapter three focuses on the reaction of bis(dialkylamino)phosphines with
decaborane and describes the synthesis of the nido-[l-nido-?^\o\\\2\ anion in high
yield. In Chapter four, the use of the nido-[l-PB}oH\2\ anion to prepare a range of
cluster complexes via reaction with a variety of electrophiles is discussed. Chapter
five focuses on the reaction of bis(dialkylamino)phosphines with nido-5,6-
dicarbadecaborane(12) and describes the synthesis of novel compounds of the
formulae 6,9-R2NHP-5,6-C2 Bs Hn, (R = Pr', Bu1 ). This is considered as an
intermediate product which subsequently gives a mixture of the nit/<>-7,8,\ 1-
PC2B8Hn, mWo-[7,8,9-PC;>BxHio]~ and /m/o-[7,8,l 1-PC:B8 H IO ] species whose ratio is
dependant on the R group. Each chapter contains a brief introduction, discusses the
results obtained including multinuclear NMR spectroscopy and crystal structure data
and concludes with an experimental section.

Citation

Guest, A. Precursors for doped boron carbide thin films. (Thesis). Salford : University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 3, 2012
• Award Date: Jan 1, 2010