Thermal Annealing Effect on the Structure, Optical and Electrical Properties of Lanthanum Manganite Thin Films Prepared by Reactive Co-Sputtering

Lanthanum manganite (LMO) thin films were deposited by co-sputtering La and Mn targets in an Ar and O2 gas mixture. The films were synthesized on silicon and fused silica substrates. The influences of thermal annealing on the structure, optical and electrical properties of LMO films were investigated. The results exhibited a correlation between these properties. In the amorphous state, an increase in annealing temperature improved the optical transmission and decreased the electrical capacitance. The beginning of crystallization at 600 °C was manifested by a strong increase in the capacitance and a decrease in the optical transmission. At higher annealing temperature, polycrystalline films were obtained with different optical and electrical characteristics. On the other hand, the annealed LMO films showed a photocurrent effect during exposure to a weak LED light.