Emily S. Peters

Atmospheric pressure chemical vapour deposition of WS2 thin films on glass

The atmospheric pressure chemical vapour deposition reaction Of W(CO)(6), WOCl4 or WCl6 with HS(CH2)(2)SH or HSC(CH3)(3) at 350-600degreesC leads to thin films Of WS2 on glass substrates. The WS2 films were nanocrystalline, showed a W:S ratio of 1:2 by EDAX and gave Raman bands at 416 and 351 cm(-1). The films were silver or gold in colour, adhesive to the substrate and showed Volmer-Webber type growth by SEM. Optical band gaps were 1.4 eV. The films were reflective in the visible region and transparent in the near IR

Titanium sulfide thin films from the aerosol-assisted chemical vapour deposition of [Ti(SBut)4]

Gold, reflective TiS2 films have been produced from the single-source precursor [Ti(SBut)4] by aerosol-assisted chemical vapour deposition on glass. Films were deposited between 150 and 300 °C using hexanes, dichloromethane or toluene solvent. The titanium sulfide films were analysed by Raman, UV-Vis spectroscopy, scanning electron microscopy (SEM), X-ray powder diffraction, energy dispersive analysis of X-rays (EDAX) and X-ray photoelectron spectroscopy (XPS).

Dual-source chemical vapour deposition of titanium sulfide thin films from tetrakisdimethylamidotitanium and sulfur precursors

The dual-source atmospheric pressure chemical vapour deposition (APCVD) of TiS2 thin films from [Ti(NMe2)4] and ButSH is presented. Deposition took place at low temperatures (175–500 °C) and nitrogen and carbon contamination of the films was negligible. The APCVD reaction of [Ti(NMe2)4] and But2S2 resulted in the formation of a TiS2 film at 600 °C but at 300–550 °C films with a Ti:S ratio of 1:1 by EDXA were produced. In contrast, films produced from [Ti(NMe2)4] and S(SiMe3)2 at 350–600 °C contained little sulfur (TiS0.1–0.3) but large amounts of nitrogen and carbon indicating that titanium carbonitride (TiC0.5N0.5) had formed. The films were characterised by EDXA, SEM, XPS and Raman spectroscopy.

Formation of a new (1T) trigonal NbS2 polytype via atmospheric pressure chemical vapour depositionElectronic supplementary information (ESI) available: structure refinements of the NbS2 films and crystallographic data in CIF format. See http://www.rsc.org/suppdata/jm/b3/b315782m/

The formation of a new trigonal polytype of niobium disulfide, 1T-NbS2, is described from the atmospheric pressure chemical vapour deposition reaction of niobium pentachloride with hexamethyldisilathiane and tert-butyl disulfide at 400–600 °C; films were grown on glass and those deposited at 500–600 °C were crystalline.

Molecular precursors to gallium oxide thin films

The donor-functionalised alkoxides [Et(2)Ga(OR)](2)(R = CH(2)CH(2)NMe(2)(1), CH(CH(2)NMe(2))(2)(2), CH(2)CH(2)OMe (3), CH(CH(3))CH(2)NMe(2)(4), C(CH(3))(2)CH(2)OMe (5)) were synthesised by the 1:1 reaction of Et(3)Ga with ROH in hexane or dichloromethane at room temperature. Reaction of Et(3)Ga with excess ROH in refluxing toluene resulted in the isolation of a 1:1 mixture of [Et(2)Ga(OR)](2) and the ethylgallium bisalkoxide [EtGa(OR)(2)](R = CH(2)CH(2)NMe(2)(6) or CH(CH(3))CH(2)NMe(2)(7)). X-ray crystallography showed that compound 6 is monomeric and this complex represents the first structurally characterised monomeric gallium bisalkoxide. Homoleptic gallium trisalkoxides [Ga(OR)(3)](2) were prepared by the 1:6 reaction of [Ga(NMe(2))(3)](2) with ROH (R = CH(2)CH(2)NMe(2)(8), CH(CH(3))CH(2)NMe(2)(9), C(CH(3))(2)CH(2)OMe (10)). The decomposition of compounds 1, 4, 5 and 8 were studied by thermal gravimetric analysis. Low pressure CVD of 1 and 5 resulted in the formation of thin films of crystalline Ga(2)O(3).

Reactivity of tetrakisdimethylamido-titanium(IV) and -zirconium(IV) with thiols

The reaction of [M(NMe2)4] (M = Ti, Zr) with thiols has been investigated. Reaction of [Ti(NMe2)4] with an excess of CF3CH2SH in hexanes at room temperature resulted in the formation of the ionic complex [Me2NH2]2[Ti(SCH2CF3)6] (1). The related reaction between [Zr(NMe2)4] and 4 equivalents of ButSH at room temperature resulted in the isolation of the ionic complex [Me2NH2][Zr2(μ-SBut)3(SBut)6] (2). In contrast, reaction of [Zr(NMe2)4] and 4 equivalents of 2-mercaptopyridine (HSC5H4N) afforded the neutral complex [Zr(SC5H4N)4] (3). Compounds 1 and 2 have been characterised by X-ray crystallography. Low pressure CVD of [Me2NH2]2[Ti(SCH2CF3)6] produced purple films of TiS2 on glass substrates at 550 °C.

The use of hexamethyldisilathiane for the synthesis of transition metal sulfides

The reaction of TiCl4 with hexamethyldisilathiane in diethyl ether at room temperature affords black precipitates which upon annealing under H2S at 800 degreesC results in the formation of crystalline TiS2. Similarly, reaction Of MCl5 (M = Nb, Ta, Mo) with S(SiMe3)(2) in diethyl ether at room temperature or toluene at reflux results in the initial formation of black precipitates MxSyClzSipCqHp. Annealing of these precipitates under static vacuum at 550 or at 800 degreesC under H2S affords MS2. The black precipitates and metal sulfides produced under all annealing conditions were analysed by powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and Raman spectroscopy