Laser wavelength effect on structural and optical properties of Cd34Se66 nanocrystalline thin film

Cadmium Selenide (Cd34Se66) thin films are deposited on a glass substrate using the thermal evaporation method at room temperature. The Cd34Se66 films are characterized using XRD. The crystallite size of the film is calculated from XRD data, which is found as 29.61 nm as-deposited. It is also found that crystallite size of Cd34Se66 changed after irradiation with N2 and Nd:YAG laser. The changes in the optical properties of the films after irradiation with N2 laser and Nd:YAG laser are also studied in the wavelength range of 300–700 nm and it is found that the optical band gap of the Cd34Se66 films changed after laser irradiation.

Research Highlights
► N2 laser irradiation of Cd34Se66 thin film causes up to threefold increase of the crystallite size.
► It also transforms the film from hexagonal to cubic and results in slight decrease in its band gap.
► Irradiation of the film by 532 nm Nd:YAG laser results in two fold decrease of the crystallite size.
► However, the optical band gap is found to increase considerably due to the nanostructure phase.