Crystalline Thin Layers of BaTiO3 for Gas Sensors Prepared by PLD

Abstract

The synthesis of BaTiO3 thin films for gas detectors was studied. Thin layers of BaTiO3 (BTO) were deposited by pulsed laser deposition (PLD) on fused silica and Si (100) substrates using various deposition conditions from a sintered BaTiO3 target. The energy density of a KrF excimer laser was in the range from 2 to 6 Jcm−2. Films were deposited in an O2 ambient in the range from 10−3 to 10 Pa. The films were prepared at substrate temperatures ranging from 500 to 980 °C. Polycrystalline BTO was obtained at substrate temperatures above 670 °C. With increasing deposition temperature above 700 °C the formation of the unwanted rutile phase prevented the growth of perovskite ferroelectric BTO. Concurrently, with decreasing substrate temperature below 670 °C, amorphous films were formed. The layers was characterized by XRD spectroscopy and AFM microscopy. We optimized the depositions condition of the layers for chemical sensors.