Comparative study of optical properties of ZnO and Zn_0.95La_0.05O thin films

In the present work, transparent ZnO and Zn_0.95La_0.05O films were prepared at a deposition temperature of 400 ⁰C on the glass substrate through the chemical spray pyrolysis technique. The precursor solutions were prepared by using salts such as Zinc acetate dihydrate, Lanthanum chloride heptahydrate, and double distilled water as the solvent. The optical band gap values were observed to be considerably dependent on La ion dopant, which can be explained using Burstein-Moss (B-M) shift. Urbach energy increases from 108.386 meV to 160.295 meV for ZnO and Zn_0.95La_0.05O films respectively, indicating poor crystallinity of the deposits with La content. According to the photoluminescence (PL) investigation, La ion doping increased the intensity of impurity levels in the bandgap of the host matrix, which can broaden its visible-light sensitivity, making it advantageous for potential useful applications. Hence, these results indicated that lanthanum doping plays a vital role in tuning the optical bandgap and photoluminescence property of the ZnO nanostructure.