X-RAY-DIFFRACTION STUDIES OF THE STRUCTURE OF MOLYBDENUM SULFIDE THIN-FILMS

The structure of thin films of molybdenum sulphide (MoS2) deposited on silicon substrates has been investigated as a function of temperature using X-rav diffraction and transmission electron microscopy. The ini tial state of the films is characterised by microcrystals with a diame ter of around 2 nanometres. Thermal treatment leads to an increase in grain size to around 20 nm at 900-degrees-C. A continuous reduction in the c lattice parameter is observed during heating. Prior to heat tre atment the structure of the film is dependent upon film thickness. Upo n heating these differences are observed to disappear. Isothermal meas urements of the diffraction pattern at elevated temperatures show only slight changes in the structure with time. The final state of the MoS 2 is similar to that of bulk polcrystalline molybdenum sulphide.