Effect of swift heavy ion irradiation on structural and opto-electrical properties of bi-layer CdS–Bi2S3 thin films prepared by solution growth technique at room temperature

• Preparation of samples by chemical bath deposition technique.
• The thin films were annealed in an air atmosphere for 1 h. at 250 °C.
• Annealed sample irradiated by 120 MeV energy Au9+ ions at fluence 5×1012 ions/cm2.
• Study of modification induced by air annealing and irradiations.

CdS–Bi2S3 bi-layer thin films have been deposited by chemical bath deposition method on Indium Tin Oxide glass substrate at room temperature. The as-deposited thin films were annealed at 250 °C in an air atmosphere for 1 h. An air annealed thin film was irradiated using Au9+ ions with the energy of 120 MeV at fluence 5×1012 ions/cm2 using tandem pelletron accelerator. The irradiation induced modifications were studied using X-ray diffraction (XRD), Atomic Force Microscopy (AFM), Raman spectroscopy, UV spectroscopy and I–V characteristics. XRD study reveals that the as-deposited thin films were nanocrystalline in nature. The decrease in crystallite size, increase in energy band gap and resistivity were observed after irradiation. Results are explained on the basis of energy deposited by the electronic loss after irradiation. The comparative results of as-deposited, air annealed and irradiated CdS–Bi2S3 bi-layer thin films are presented.