Precursor synthesis and chemical vapour deposition of group 13 oxides.

This thesis is primarily concerned with the precursor synthesis and chemical vapour deposition of group 13 oxides. The gas sensing properties of some of the films prepared have also been investigated. Chapter 1 gives an introduction to techniques used for deposition, in particular chemical vapour deposition (CVD). Chapter 2 describes the synthesis of gallium and indium alkoxides incorporating donor functionalised ligands. The donor-functionalised alkoxides (R2M(OR') 2 (M = Ga. R = Et M = In, R = Me R' = CH2CH2NMe2. CH(CH2NMe2)2. CH2CH2OMe. CH(Cfh)CH2NMe2, C(CH02CH2OMe) were synthesised by the 1 : 1 reaction of RM with R'OH in toluene at room temperature. Gallium and indium bis-alkoxides RM(OR')2 (M = Ga, R = Et M = In, R = Me R' = CH2CH2NMe2. CH(CH2NMe2)2. CH2CH2OMe. CH(Chh)CH2NMe2, C(CrhhCH2OMe) have also been synthesised by the 1 : 6 reaction of RiM with R'OH in toluene under reflux conditions. Homoleptic gallium trisalkoxides Ga(ORb 2 have been prepared by the 1 : 6 reaction of Ga(NMe2h 2 with R'OH. Decomposition of all the compounds have been studied by thermal gravimetric analysis in Chapter 3. The formation of thin-films of gallium oxide via single-source low pressure chemical vapour deposition (LPCVD) methodology was investigated including detailed film growth studies and characterisation. The compounds described above were used as precursors and deposition was achieved at 550 C. Chapter 3 also investigates the formation of thin-films of gallium and indium oxide using aerosol assisted chemical vapour deposition (AACVD). This involved the in situ reaction of Ga(NMe2)3 2 or RjM with a donor functionalised alcohol (R'OH). Gas sensing experiments on selected Ga2Oi films deposited by AACVD are described in Chapter 4