Structural and optical characterization of pulsed laser-ablated potassium lithium niobate thin films

Abstract

Thin films of potassium lithium niobate (K, Li, Nb-O, KLN) have been prepared on glass substrate as a functional substrate temperature, using a pulsed laser deposition (PLD) technique or the first time. Grazing-incidence x-ray diffraction (GIXRD) analysis suggests that KLN films can be grown successfully at a substrate temperature as low as 300 K. The anomalous behavior of the decline of crystallin structure with increase in substrate temperature is explained. The atomic force microstructure (AFM) and scanning electron microscopic (SEM) images show an agglomerated growth mode for the films deposited a substrate temperature of 300 K and a decrease in grain size with increase in substrate temperature. The films deposited at higher substrate temperatures show ring-like structures. The AFM analysis shows that the rms surface roughness of the film decrease with increase in substrate temperature. The UV-Vis transmission spectra suggest that the nature of the transition in the films is directly allowed. A blue shift in optical bandgap is observed for the films compared to bulk material. The changes in the optical bandgap with substrate temperature are also discussed.