Comparison of the electro-optical performance of ZnO:Al and ZnO:B thin films derived by sol-gel method

Abstract

Aluminum doped zinc oxide (AZO) and Boron doped zinc oxide (BZO) thin films with excellent electro-optical properties were prepared by sol-gel dip-coating process. The diversified performance of AZO and BZO were analyzed from radius of doped atoms, type of the doping defects, the stability of the formed coordination polyhedron, energy band structure aspects. Also the effects of annealing atmosphere on the electro-optical property were investigated. The phase, microstructure and electro-optical properties of the films were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), four-probe resistance meter, hall effect tester and UV-visible-infrared spectrophotometer, respectively. The view put forward from coordination polyhedron perspective can be generalized to other materials with impurity doped to judge the stability of ionic crystal or metallic crystal lattice structure. The results show that AZO thin films exhibit much better electric properties, the annealing atmosphere is crucial for enhancing the electrical performance of the films. The best sheet resistance and resistivity of AZO films are about 166Ω/sq. and 1.99×10−3Ω·cm and that of BZO are about 360Ω/sq. and 4.01Ω·cm, respectively. The mean visible light transmittance of the films is about 80%.