Transition metal dichalcogenides (TMDs) exhibit a wide range of interestingproperties and potential applications. The major barrier to the use of these materials in devices is the formation of high quality thin films. Chemical vapour deposition (CVD) is a scalable technique which can provide high quality thin films over large areas. The principal objective of this work is to synthesise and characterise a range of single-source precursors for the deposition of metal disulfides.Chapter 1 provides an introduction to the applications, properties and synthesis of TMDs. An overview of CVD highlights the major variants used while the majorclasses of metal chalcogenide single-source precursors are reviewed.Chapter 2 describes the synthesis, characterisation and structures of group IV metal thioureide complexes formed by the insertion of isothiocyanates into group IV metal amides. Heteroleptic and homoleptic group IV metal dithiocarbamates are also investigated with selected complexes used as precursors in aerosol-assisted CVD (AACVD) and low pressure CVD (LPCVD) experiments.Chapter 3 describes the synthesis, characterisation and structures of tantalumthioureide complexes formed by the insertion of isothiocyanates into PDMAT or[(tBuN)Ta(NMe2)3]. Thermal decomposition studies of these complexes are discussed. tert-butylimide based tantalum dithiocarbamates are also investigated as both AACVD and LPCVD precursors for the deposition of TaS2.Chapter 4 describes the synthesis, characterisation and structures of group VI metal thioureide complexes formed by the reactions of bis(tert-butylimido)bis(amido) group VI metal complexes and either isothiocyanates or disubstituted thioureas. The suitability of these complexes as AACVD precursors is explored. Homoleptic group VI metal dithiocarbamates and xanthates are also investigated as AACVD precursors. Deposition of WS2 onto graphene substrates is studied using the precursor [W(S2CNEt2)4].Chapter 5 contains experimental procedures and characterisation data for thecomplexes and thin films described.Appendix lists the crystal structure refinement tables and EDX analysis spectra.
|Date of Award||26 Apr 2017|
|Supervisor||Andrew Johnson (Supervisor) & Daniel Wolverson (Supervisor)|