The effect of Co and Mn Co-Doping on structural and optical properties of ZnO thin films

Abstract

Doped thin films are attractive for future sensors, solar cells, and optics materials. In the present study, Co and Mn co-doped ZnO thin-films were deposited on the glass substrate using the sol-gel spin coating method. Their structural and optical properties were investigated using XRD, SEM with EDX, UV–Vis, Photoluminescence (PL), FTIR, and Raman spectroscopy. The nanofiber-like structure obtained from the SEM images revealed that the co-doping effect created a stable structure on the film. The highest optical band was observed in the Z23 (2% Mn and 3% Co) sample with a value of 3.18 eV. The PL spectrum of ZnO thin films had a sharp emission peak centered at 379 cm−1 in the ultraviolet region and a broad excitation peak centered at 560 cm−1 in the visible range. The addition of Mn and Co to the ZnO host matrix caused the peak to split and degrade at 460 cm−1 in FTIR spectra. Raman spectra showed that Mn(II) and Co(II) metals are bonded with oxygen atoms in the ZnO structure, and this proves that the energy holding capacity is increased due to the red region shift.