XRD and XPS characterization of mixed valence Mn_3O_4 hausmannite thin films prepared by chemical spray pyrolysis technique

摘要

Spray pyrolysis technique has been employed successfully for the synthesis of single phase mixed valence spinel hausmannite (Mn_3O_4) thin films using alcoholic start solution of manganese acetate (Mn(CH_3COO)_2·4H_2O) on pyrex glass substrates at atmospheric pressure using air as a carrier gas. Thermal decomposition of the precursor in the temperature range 320-490 ℃ led to the formation of Mn_3O_4 phase as revealed from the thermogravimetry analysis. Prepared samples are characterized by X-ray diffraction that shows spinel structure with space group 14_1/amd. Pure and well crystallized specimen is subjected to X-ray photoelectron spectroscopy for the surface chemistry investigation of these systems at a molecular level. Surface Mn/O ratio is compared to the bulk composition of the sample. Atomic force micrographs revealed that the morphology and the surface grains of the films largely influenced by the substrate temperature.