Modified sol–gel preparation of LiNbO3 target for PLD

Abstract

When preparing LiNbO3 thin layer by PLD, the maximal density of polycrystalline target is important. In this work, we prepared the precursor powders by sol–gel method and used them at PLD target synthesis. The gels were synthesized by Pechini polyesterification, using citric acid and ethylene glycol as an organic matrix constituents, and then decomposed using various temperatures (800, 600 and 400°C) and atmospheres (air, nitrogen and oxygen in sequence). Out of several combinations tested, the decomposition at 800°C in nitrogen followed by the oxidation at 400°C in oxygen was found to be the best way to achieve the minimal particle size of powder precursor resulting in denser targets. The prepared targets were characterized by XRD and SEM.The optimized process was subsequently used for preparation of LiNbO3 target. Thin layers prepared by PLD from this target resulted smoother than the layers prepared from commercial monocrystalline target.