Sol–gel synthesis and transport property of nanocrystalline La2Mo2O9 thin films

La2Mo2O9 films were successfully synthesized on silicon (100) and poly-alumina substrates via modified sol–gel method with inorganic salts of La(NO3)3 and (NH4)6Mo7O24 as precursors. Pure La2Mo2O9 phase was confirmed by XRD if the annealing temperature was higher than 500 °C. Energy dispersive spectrometry (EDS) of TEM revealed that the molar ratio of La to Mo was nearly 1:1. Field-emission SEM characterization showed that the films were dense, crack-free and uniform. The grain size of the films ranged from 30 to 400 nm depending upon the calcination temperature and duration time. The roughness calculated from AFM topography varied in the range between 10 and 35 nm. The thickness of the films was more than 200 nm for single-layered films. The electrical conductivity of the films reaches 0.06 S/cm at 600 °C that was almost more than one order of magnitude higher than that of the corresponding bulk material.