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This critical review focuses on the solution based chemical vapour deposition (CVD) of main group materials with particular emphasis on their current and potential applications. Deposition of thin films of main group materials, such as metal oxides, sulfides and arsenides, have been researched owing to the array of applications which utilise them including solar cells, transparent conducting oxides (TCOs) and window coatings. Solution based CVD processes, such as aerosol-assisted (AA)CVD have been developed due to their scalability and to overcome the requirement of suitably volatile precursors as the technique relies on the solubility rather than volatility of precursors which vastly extends the range of potentially applicable compounds. An introduction into the applications and precursor requirements of main group materials will be presented first followed by a detailed discussion of their deposition reviewed according to this application. The challenges and prospects for further enabling research in terms of emerging main group materials will be discussed. [ABSTRACT FROM AUTHOR]

The β-ketoimine ligand [(Me)CN(H){iPr}–CHC(Me)=O] (L1H) and the bis(β-ketoimine) ligands [(CH2)2{N(H)C(Me)–CHC(R)=O}2] (L2H2, R = Me; L3H2, R = C6H5) linked by ethylene bridges have been used to form aluminium and gallium complexes: [Al(L1)Et2] (1), [Ga(L1)2Cl] (2), [AlL2(OiPr)] (3) and [GaL3Me] (4). The complexes were characterised by NMR spectroscopy, mass spectroscopy, and single crystal X-ray diffraction, with the exception of 1 which was isolated as an oil. Compounds 1–4 have been used for the first time as single source precursors for the deposition of Al2O3 (1, 3) and Ga2O3 (2, 4) respectively. Thin films were deposited via aerosol assisted (AA)CVD with toluene as the solvent. [ABSTRACT FROM AUTHOR]

Amidoenoate (AME = {ethyl-3-(R-amido)but-2-enoate}) complexes of aluminium and gallium, of the type: [AlCl2(AMER)] R = iPr (1-Al); [AlCl(AMER)2] R = iPr (2-Al), Dip (3-Al); [GaCl2(AMER)] R = iPr (1-Ga) and [GaCl(AMER)2] R = iPr (2-Ga), Dip (3-Ga), have been synthesised (iPr = isopropyl, Dip = 2,6-diisopropylphenyl). The coordination chemistry of these complexes has been studied in relation to precursor suitability. Investigations into the reactivity of the aluminium and gallium amidoenoate complexes involved reactions with hydride sources including alkali metal hydride salts, alkylsilanes, and magnesium hydride species and magnesium(I) dimers. The isolation of alkyl metal amidoenoate precursors including an aluminium hydride amidoenoate, [AlH(AMEDip)2] (4-Al) and dimethyl gallium amidoenoates [GaMe2(AMEDip)] (4-Ga), [GaMe2(AMEiPr)] (5-Ga) concluded the synthetic studies. A selection of the isolated complexes were used as precursors for aerosol assisted chemical vapour deposition (AACVD) at 500 °C. Thin films of either amorphous Al2O3 or Ga2O3 were deposited and subsequently annealed at 1000 °C to improve the materials' crystallinity. The films were characterised by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), UV-visible (UV-vis) spectroscopy and energy dispersive X-ray analysis (EDXA). [ABSTRACT FROM AUTHOR]

Macrocyclic [Fe(η5-C5H4Se)2M(η5-C5H4R)2]2 [M = Ti (1), Zr (2), Hf (3), R = H; and M = Zr (4), Hf (5), R = tBu] were prepared and characterized by 77Se NMR spectroscopy and the crystal structures of 1–3 and 5 were determined by single-crystal X-ray diffraction. The crystal structure of 4 is known and the complex is isomorphous with 5. 1–5 form mutually similar macrocyclic tetranuclear complexes in which the alternating Fe(C5H4Se)2 and M(C5H4R)2 centers are linked by selenium bridges. The thermogravimetric analysis (TGA) of 1–3 under a helium atmosphere indicated that the complexes undergo a two-step decomposition upon heating. The final products were identified using powder X-ray diffraction as FexMSe2, indicating their potential as single-source precursors for functional materials. [ABSTRACT FROM AUTHOR]