Deposition of SrCO₃ thin film consisting of self-assembled bundles of nanostructures by a plasma-enhanced liquid injection chemical vapour deposition technique

In this work, we demonstrate the deposition of SrCO₃ thin film consisting of SrCO₃ nano rods by a liquid injection plasma enhanced chemical vapour deposition (PE-LICVD). The precursor, Sr(thd)₂tetraglyme (thd: 2,2,6,6-tetramethyl heptanedione) dissolved in tetrahydrofuran was used as Sr source for the deposition of thin film at a substrate temperature of 350 °C in Ar plasma. Thermal stability of Sr precursor was studied using dynamic TG/DTA in an inert Ar atmosphere at a heating rate of 10 °C/min, which revealed the complex to undergo two stepped weight loss indicating a partial cracking of ligand molecules, leading to an end residue of 1.9% at 429 °C. The equilibrium vapour pressure measurement of the Sr precursor by a TG-based transpiration technique using ClausiusClapeyron relation yielded a value of 92.5 ± 0.9 kJmol⁻¹ for the enthalpy of sublimation (ΔH°_sub) in the temperature range of 500–573 K. The XRD pattern of the coatings revealed SrCO₃ to be in orthorhombic phase and is sufficiently crystalline in nature. The SEM analysis of the thin film revealed the growth of dump-bell shaped SrCO₃ nanostructures and the mean size of the SrCO₃ nanorods to be 70 ± 11 nm. The direct band gap evaluation of SrCO₃ by Tauc method using a Diffuse Reflectance Spectra yielded a value of 3.10 eV.