Doç. Dr. Şerife H. Yalçın "Fundamentals and Novel Applications of Laser Induced Breakdown Spectroscopy" konulu sunumunu LATARUM Seminerleri kapsamında 11/03/2009 tarihinde Merkezimizde gerçekleştirdi.
Assist. Prof. Dr. İdris KABALCI " OPTICAL CHARACTERIZATION OF N-DOPED TiO2 THIN FILMS BY USING PULSED LASER DEPOSITION (PLD) TECHNIQUE" has made a presentation, titled as. We thank Assist. Prof. Dr. İdris KABALCI from Harran University for giving information about pulsed laser deposition of thin films technique.
Abstract: The Pulsed Laser Deposition (PLD) is a flash evaporation technique. A short, high energy pulse from an excimer laser strikes the solid's surface. The fraction of energy absorbed creates a thermal pulse that rapidly spreads into the bulk evaporant, perpendicular to the surface. Here we present our results exploiting the versatility of pulsed laser deposition (PLD) for growing TiO2-xNx films of increased N content. Nitrogen-doped titanium dioxide (TiO2-xNx) is a photocatalytically active material with extended absorption in the visible spectral range. Increasing the nitrogen content of these films beyond the typical maximum at 2 at.% is an ongoing and important issue for all film preparation techniques. Ti targets were ablated by 248 nm pulses of a KrF excimer laser and the N content of the films (0 < x < 0.08) was varied by changing the nitrogen/oxygen flow ratio at a fixed 5 Pa total pressure. Optical characterization was made by UV-VIS spectrophotometry and variable angle spectroscopic ellipsometry with complementary profilometry for measuring the thickness of the films. With increasing N content the band gap of the films decreases from 3.3 to 2.6 eV while the absorption edge shifts towards the visible region. The effect of substrate temperature on the band gap of the PLD grown films is also presented.
