Picosecond ultrafast pulsed laser deposition of SrTiO3

SrTiO3 particle-composed films were grown on Si substrates via picosecond ultrafast pulsed laser deposition. We have investigated the effect of laser pulse repetition rate (0.2-8.2 MHz) and fluence (0.079-1.57 J cm−2) on the morphology, crystallinity and stoichiometry of the films. X-ray diffraction, energy dispersive X-ray spectroscopy and Rutherford backscattering spectroscopy measurements demonstrated that the as-grown films were nearly stoichiometric and composed of large particles when a pulse repetition rate of 0.2 MHz was employed. However, at the higher repetition rate of 8.2 MHz the particle size decreased and the stoichiometry was altered. Finally, we attribute the formation of micron-size particle-composed films to the slow translation speed in relation to the high pulse repetition rates (kHz-MHz regime).