A Surface Chemistry Route to Molybdenum Sulfide and Germanide Films Using the Single-Source Precursor Tetrakis(diethylaminodithiocarbomato)molybdate(IV)

Abstract

We report for the first time the direct deposition of crystalline molybdenum sulfide (MoS2) using a single-source precursor based on tetrakis(diethylaminodithiocarbomato)molybdate(IV) (abbreviated as Mo(Et2NCS2)4). The chemistry of this precursor adsorbed on a range of substrates (silicon, germanium, gold-coated germanium, nickel, etc.) has been studied using in situ X-ray photoelectron spectroscopy. The Mo(Et2NCS2)4 precursor can be evaporated at 300 °C; its vapor adsorbs on most surfaces at room temperature and decomposes by 400 °C to form crystalline MoS2. Using this method, high-quality, basal plane-oriented MoS2 can be grown on nickel by a one-step thermal evaporation process for the first time. Interestingly, choosing elemental substrates which form eutectic alloys with gold favors the elimination of sulfur from the MoS2 film. This results in Mo intermetallic compound formation at the eutectic temperatures of the Au and substrate element. Unpredecented low-temperature growth of tetragonal MoSi2 or orthorhombic MoGe2 on Au-coated silicon or germanium, respectively, has been obtained via this eutectic phase-mediated diffusional reaction. Hollow carbon nanofibers are produced if the precursor is dosed onto Au−Si substrate at 1000 °C, mediated by the catalytic effect of Au−Mo.

Chemical vapour deposition of rhenium disulfide and rhenium-doped molybdenum disulfide thin films using single-source precursors

“…Synthesis and characterisation of the rhenium and molybdenum precursors Re(m-S i Pr) 3 (S i Pr) 6 (1) and Mo(S 2 CNEt 2 ) 4 (2) were synthesised by literature procedures. 44,45 All characterisation data matched with that previously reported. Complex (1) was a dark red powder, whilst complex (2) appeared as dark purple crystals.…”

“…A mixture of Mo(CO) 6 (10 g, 37.8 mmol) and bis(diethylthiocarbamoyl)disulfide (22.4 g, 75.6 mmol) was dissolved in degassed acetone (400 mL) and heated under reflux at a temperature range of 55-60 1C for 2 h. The mixture was cooled to room temperature, which prompted violet crystals to appear which were filtered and washed with pentane and dried in vacuo, 45 Argon was used as inert gas carrier with flow rate 180 sccm in to the furnace where precursors decomposed and deposit on the glass substrates (1 Â 2 cm), which has been ultrasonically cleaned in isopropanol prior to use. The flow rate of argon was controlled using Platon flow gauge.…”

In-situ construction of conducting alloy interphase towards modulating Li-ion storage kinetics

“…Moreover, we observed a shift of the Mo 3d doublet to even lower binding energies at 231.6 and 228.5 eV as shown in Fig. 4(b and c), suggesting that the new phase is formed [38]. The formation of an intermediate solid (MoGe 2 ) phase is based on the reaction between liquid (Ge) and solid (MoGe 2 ) at high annealing temperature.…”

“…In addition to the relatively wide photoluminescence, there are several prominent Raman shifts that can be found in the spectrum. The first four peaks at 141, 169, 239, 252 and 290 cm À1 Raman shift correspond to MoGe 2 , and the next three Raman peak at 383, 406 and 300 cm À1 are ascribed to MoS 2 and Ge, respectively [37][38][39]. By comparison, it can be seen that as the temperature increases, new phases Ge and MoGe 2 are generated.…”

An Eco‐Friendly, CMOS‐Compatible Transfer Process for Large‐Scale CVD‐Graphene

“…In contrast, as the portion of amorphous phase decreased with increasing temperature, the etching time linearly increased (Figure c) . However, if the heating treatment is performed at 200 °C, the MoO 3 film is partially peeled off with graphene from the Ge substrate, due to the alloying of Ge and Mo (Figure S7, Supporting Information) …”