Microstructural and optical properties of dysprosium doped copper oxide thin films fabricated by pulsed laser deposition technique

Thin films of pure and dysprosium doped (1, 2, 3 and 5 at. wt%) copper oxide (Dy-CuO) are deposited onto p-silicon (1 0 0) substrate using pulsed laser deposition technique under vacuum at 300 °C. Dy doping concentration considerably influences the microstructure, surface morphology and optical properties of CuO thin films. All the films exhibit polycrystalline nature. The reduced crystallite size and blue shifted Raman peaks are observed for Dy doped CuO thin films as compared to phase pure film. Surface morphology reveals that CuO thin film is porous while doped thin films are dense but have particulates. Optical bandgap energies (Eg) of Dy-CuO thin films are found to be higher than phase pure CuO thin film. 1 % Dy-CuO thin film exhibits lowest crystallite size, maximum blue shift in Raman peak position and highest optical bandgap energy among all thin films. The higher values of Eg for doped films are attributed to the production of compressive stresses (confirmed by XRD and Raman results) upon doping, which form new trap levels within the valence band. This work has potential applications in optical and optoelectronic industries.