Effect of substrate temperature on optical, structural and electrical properties of FeSe thin films deposited by spray pyrolysis technique

•Nanocrystalline FeSe thin films were prepared at various substrate temperatures.•Physical properties of films were influenced by deposition temperature.•The films were p-type semiconducting with tetragonal lattice.

The versatile spray pyrolysis technique was employed to prepare thin films of iron selenide on glass substrates at different substrate temperatures. The deposition temperature was varied between 473 and 673 K. The as-deposited films were characterized by X-ray diffraction (XRD), SEM, optical and electrical characterization techniques. The X-ray studies reveal that the films are nanocrystalline with tetragonal structure and exhibit (101) preferred orientation. The SEM and AFM studies indicate that the film surface is homogenous with no cracks or pinholes and well covers the glass substrate. The film thickness was found to vary from 110 to 230 nm with substrate temperature. The optical band gap was found to decrease from 2.92 to 2.68 eV depending on deposition temperature. The resistivity of p-type FeSe film is of the order of 8×104 Ω cm and it decreases to 1.5×104 Ω cm as substrate temperature is increased from 473 K to 673 K.

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