Unveiling of influence of aluminum incorporation on the structural, optical, and magnetic characteristics of Gd-doped ZnO

This paper presents the properties of ZnO thin films enhanced by the incorporation of Gd (3 at%) and Al (3 at%), which were synthesized using a simultaneous target sputtered onto glass substrate. Using X-ray diffractometer, the crystalline structure of the films was determined showing the effective incorporation both doping elements into ZnO lattice. This has been proved as no secondary phases or any peaks associated to Gd and Al in the deposited films. EDS results further demonstrated the presence of Gd and Al ions within films with amount of concentration were 3 at% for each respective element. The surface morphology exhibited homogenous nanoparticles structure for all the deposited films in which the nanoparticle size became smaller as Gd and Al were added to ZnO films. The optical properties by UV-Vis showed good transmittance that surpassing 90 % of average transmittance for all the films. The bandgap obtained using Tauc's plot equation based on the transmittance results were increased when both Gd and Al were incorporated. The magnetic properties of the co-doping films were obtained using magnetic force microscopy (MFM). The results showed that the MFM images for the film incorporating Gd and Al had a bright-dark contrast as compared to the undoped one. It further unveils improved magnetic properties, as evidence by its larger value of δƒrms. Based on these findings, adding 3 at% of Al to the Gd-doped ZnO films has further enhanced its physical, optical and magnetic characteristics, which in turn could also improve its magnetic behaviour at room temperature.