Influence of the complexing agent (Na2-EDTA) on the structural, morphological, electrical and optical properties of chemically deposited FeSe thin films

• Nanocrystalline tetragonal FeSe thin films were successfully prepared by CBD method.
• The effect of EDTA complex on growth process is discussed.
• The structural, electrical and optical properties were discussed as a function EDTA volume.
• The porous nature of film increases with EDTA which may be suitable for many optoelectronic devices.

Nanocrystalline iron selenide thin films have been successfully prepared by chemical bath deposition route onto glass substrates using Fe (NO3)3·9H2O and Na2SeSO3 as Fe and Se source with disodium salt of ethylene diaminetetraacetic acid as complexing agent. Seven different sets of these films were prepared by varying the quantity of EDTA in deposition bath. The structure and morphology of the FeSe thin films were characterized by XRD, EDAX and SEM. The prepared films are nanocrystalline in nature with tetragonal crystal structure and show mixed phase of Fe3Se4 and FeSe at lower thickness. The morphology of films showed that the growth mechanism is highly influenced by the quantity of EDTA added in the reaction bath. The variation in optical band gap, electrical resistivity and activation energy with the addition of Na2-EDTA in reaction bath confirms improved morphology of FeSe which can be utilized in solar energy conversion devices.

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