Effect of Mn Doping on Structural and Optical Properties of ZnO Thin Films Prepared on Glass Substrates by Sol-Gel Method

Abstract

Thin films of Zn1-xMnxO (x = 0.00, 0.03, 0.07, 0.10) were prepared onto glass substrates by sol-gel spin-coating technique. The structural, morphologic and optical properties of these samples were studied respectively. The XRD patterns show the thin films are all polycrystalline with hexagonal wurtzite structure and no preferred orientation. With the increase of Mn doping, the c-axis lattice constants of the samples shift towards higher values until the doping concentration reaches up to 7%. This indicates that Mn2+substituted for Zn2+of ZnO host. Moreover, the grain size decreases gradually with the increase of Mn doping content. The AFM results indicate surface roughness increases with the increase of Mn doping level. The photoluminescence spectra reveal Mn doping causes a blue shift of the UV peak. The intensity of UV emission peaks increases at the beginning and then decreases with the increase of Mn doping content.