Group 13 metal oxide and pnictide thin films: developing novel single-source precursors for the deposition of functional materials

This thesis describes the synthesis and characterisation of molecular, single-source precursors for the deposition of group 13 metal oxides and pnictides and their subsequent application in the formation of thin films of those materials by Aerosol Assisted Chemical Vapour Deposition (AACVD). A range of tetradentate β-ketoimine ligands have been developed and subsequently employed in the formation and isolation of complexes of group 13 metals aluminium, gallium and indium through a variety of synthetic routes. In particular, the ligand systems have been successfully employed in the stabilisation of rare gallium mono-hydride species, which exhibit considerable thermal stability. The thermal decomposition of the group 13 β-ketoiminate complexes was investigated by thermogravimetric analysis and subsequently the deposition of gallium oxide was carried out on glass substrates in an AACVD process. The resulting films were amorphous as-deposited, however crystalline gallium oxide was obtained in some cases through the addition of a post-deposition annealing step. The single-source deposition of InAs by AACVD has been investigated, including an investigation of the alkane elimination reaction between trimethyl indium and tert-butyl arsine in the formation of InAs cluster complexes. InAs was successfully deposited, representing the first report of the deposition of this material by AACVD. Thin films were analysed and characterised by multiple common techniques, including glancing angle powder X-ray diffraction, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy and scanning electron microscopy, confirming the formation of InAs, though film quality was hampered by varying degrees of indium oxide formation within the films, in particular at the surface. Hall effect measurements provided an initial investigation of the electrical properties of the films, showing the formation of conductive, n-type InAs. However, electron mobility was poor by comparison to literature suggesting that optimisation of the deposition conditions is required in order to yield device-quality materials