Heteroleptic titanium alkoxides as single-source precursors for MOCVD of micro-structured TiO2

• Published in: Polyhedron 2015-01, Vol.85, p.761-769
• Main Authors: Ashraf, Sobia, Aspinall, Helen C., Bacsa, John, Chalker, Paul R., Davies, Hywel O., Jones, Anthony C., O’Brien, Paul, Wrench, Jacqueline S.
• Format: Article
• Language: English
• Subjects: Alkoxide; Microstructure; MOCVD; Precursor; TiO2
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2014.10.007

Heterolepetic titanium alkoxides with donor-functionalized ligands show greatly modified behaviour as precursors for MOCVD of TiO2 compared with their homoleptic analogues with monodentate ligands. [Ti(OPri)2(OCH2CH2NMe2)2] is found to be a highly effective single-source precursor for MOCVD of micro structured anatase. [Display omitted] [Ti(OR)4] (R=Pri or But) and their heteroleptic derivatives [Ti(OR)2(L)2] [L=bidentate donor-functionalized alkoxide: mmp (1-methoxy-2-methylpropan-2-olate) dmae (2-(dimethylamino)ethanoxide), dmop (2-(4,4-dimethyl-4,5-dihydrooxazol-2-yl)propan-2-olate) or dmom ((4,4-dimethyl-4,5-dihydrooxazol-2-yl)methoxide)] are investigated as single source precursors for liquid injection MOCVD of TiO2 on F-doped SnO2 substrates. The influence of the ligands on the phase and morphology of the deposited films is investigated, and [Ti(OPri)2(dmae)2] is found to be the most effective precursor for growth of nanostructured anatase. The identity of the monodentate alkoxide is found to have the greatest influence on the phase of the thin film: OPri-containing precursors deposit anatase under all conditions whereas OBut-containing precursors have a greater tendency to deposit rutile or mixed phases. The effect of film morphology on the photoinduced hydrophilic state is demonstrated. [Ti(OR)2(dmop)2] (R=Pri or But) have been characterised by single crystal X-ray diffraction.