Currently, single layered MoS 2 nanosheets can be obtained by top-down mechanical [1] or chemical exfoliation [2] and bottom-up chemical vapour deposition [3] process. These are difficult for making viable devices either due to their limited lateral size or being expensive respectively. The current state-of-the-art chemical vapour deposition (CVD) used to synthesize MoS 2 requires vacuum and high-purity precursors rendering it expensive and substrate also plays an important role in determining

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... he film quality. Other methods including chemical bath deposition and hydrothermal synthesis also have limitations and requires improved processing to obtain layered nanosheets. Here, novel liquid phase synthesis of MoS 2 thin films has been achieved at high temperature. Chemical conversion of the deposited Mo-precursor films on silicon/silicon dioxide substrate to MoS 2 were obtained by annealing in presence of sulfur. To increase the crystallinity of the deposited films, higher processing temperature was required. Annealing temperatures above 750 °C are necessary for the formation of films. This novel wet-chemical synthesis approach for 2D materials allows upscaling, controllable film thickness and can be used for fabrication of various electronic devices i.e. TFTs, photovoltaic cells, sensors, etc. Uniformity of the layers was proven by FIB (Focussed Ion Beam)) shown in figure 1 (a and b) . It is clearly observed that sample annealed at 900°C has uniform layers compared to lower temperatures. The planar view as could be seen in figure 1 (b) showed sulfur cluster formation at lower temperatures (was proved via EDX analyses). Larger grain boundaries were formed compared to sulphur cluster formation at higher temperatures (Figure 1-e) . To investigate this further in-situ heating was performed in TEM using the DENS heating holder (Figure 2 ). It is not trivial to observe the transition towards uniform layers in real time. Performing such in-situ heating over lamellae requires sticking the electron transparent lamellae over transparent window (on a MEMS chip - Figure 2 ). This would be dealt in more details during the presentation [4].