Orientation-Controlled Growth of Pt Films on SrTiO₃ (001) by Atomic Layer Deposition

We grew Pt films on TiO 2 -terminated SrTiO 3 (001) by atomic layer deposition, using trimethyl(methylcyclopentadienyl)-platinum(IV) as the Pt source and O 2 and O 3 as the oxidants. The orientation of the Pt films grown with O 2 varied from (111) to (001) as the growth temperature was increased from 220 to 350 °C, while the Pt films grown with O 3 have a strong preference for the (111) orientation even at a high growth temperature of 350 °C. The difference in the orientation of the Pt films on SrTiO 3 (001) was attributed to changes in the degree of chemical bonding across the Pt/SrTiO 3 interface with respect to the oxidant. We observed an increase in Pt–O bonding at the interface between the Pt grown with O 3 and the SrTiO 3 substrate. The interfacial energy of Pt (111)∥SrTiO 3 (001) may have been significantly decreased by the increase in Pt–O bonding at the interface, which eventually led to the strong (111) preference of the Pt grown with O 3 . The findings provide the possibility of controlling the orientation of Pt without manipulating the kinetic energy of crystal growth.