Effect of oxygen pressure on the optical properties of ZnO/Si(100) thin films deposited by femtosecond pulse laser

Zinc oxido (ZnO) thin films have been grown on n type Si (100) substrate using femtosecond pulsed laser deposition (PLD). The effect of change in parameters, including substrate temperature, laser energy and oxygen pressure, on the structure and optical properties of ZnO films it; discussed. The X-ray diffraction results show that the ZnO films are highly c-axis oriented: when deposited at substrate temperature of 80 degrees C with laser energy of 1.5 mJ under oxygen pressure of 1.0 mPa. The field, emission scanning electron microscopy indicates that the mean grain size increases with the increase of temperature, but decreases with the increase of laser energy. The ultraviolet-visible transmissivity shows that the annealed films have a transmittance of 90% in visible rang. The photoluminescence spectra of ZnO films are discussed. In comparison, the structure and photoluminesceme, properties of ZnO films produced by using nanosecond PLD are also studied.