In situ growth of c-axis-oriented Ca3Co4O9 thin films on Si (100)

High-quality c-axis-oriented Ca3Co4O9 thin films have been grown directly on Si (100) wafers by pulsed-laser deposition without prechemical treatment of the substrate surface. Cross-sectional transmission electron microscopy shows good crystallinity of the Ca3Co4O9 films. The Seebeck coefficient and resistivity of the Ca3Co4O9 thin films on Si (100) substrate are 126μV∕K and 4.3mΩcm, respectively, at room temperature, comparable to the single-crystal samples. This advance demonstrates the possibility of integrating the cobaltate-based high thermoelectric materials with the current state-of-the-art silicon technology for thermoelectricity-on-a-chip applications.