Effects of Mn doping concentrations on properties of ZnO thin films

Undoped and Mn doped ZnO films with different doping concentration were synthesized by sol gel method using the spin coating technique. Zn_1-xMn_xO thin films are prepared using 2-methoxyethanol solution of zinc acetate dehydrate and manganese acetate tetrahydrate. The quantity of Mn in the sol was varied for each experiment with an annealing temperature of 500°C. As to investigate the physical properties and microstructures, the samples are characterized using FESEM. The surface morphology showed spherical shaped nanoparticles and separated uniformly on the films. The quality surface degraded by doping with Mn but at until 8% of Mn, the surface become smoother. Meanwhile, the optical properties were characterized using UV-Vis where the absorbance spectra were affected by certain amount of Mn concentration. Four point probe is used to measure the resistivities of the samples. These films achieve tunable band gap characteristics by means of changing the dopant concentration.