Joseph De Mesa and Jayne Miranda, both graduate student members of Photonics, presented their most recent research work at the 7th International Congress on Laser Advanced Material Processing (LAMP) held in Kitakyushu International Conference, Fukuoka, Japan last May 26-29 2015. The abstracts of the papers presented in the conference are written below.
Optical emission spectroscopy of femtosecond pulsed laser-produced aluminum plasma
Presented by Jayne Miranda
A high purity aluminum target placed inside a vacuum chamber maintained at a base pressure of ~ 10-2 mbar was ablated using a mode-locked Ti:sapphire femtosecond laser with a wavelength centered at 786 nm, pulse repetition rate of 80 MHz and pulse duration of around 100 fs. The resulting plasma plume was then analyzed via optical emission spectroscopy. The spectra showed emission peaks corresponding to aluminum and air from 500 to 1000 nm. The presence emission peaks from air is attributed to performing ablation in a low vacuum environment.
Study of Morphological Properties and Elemental Micro-Composition of ZnO Grown by Femtosecond Pulsed Laser Deposition
Presented by Joseph De Mesa
Undoped Zinc oxide (ZnO) was successfully deposited on silicon (100) substrate by femtosecond pulsed laser deposition. A mode-locked femtosecond laser operating at 790 nm with 100 fs pulse duration and 80 MHz repetition rate was used as an excitation source. The depositions were carried out at vacuum pressures of 10-2-10-6mbar and oxygen background gas pressures of 10-2-10-4mbar. Energy dispersive spectroscopy of samples grown without oxygen background gas shows higher zinc composition on deposited material as compared to oxygen that leads to off stoichiometric ZnO films. Scanning electron microscopy (SEM) images shows that increasing oxygen gas pressure increased the particle size of the deposited ZnO. The material deposited at 2×10-4mbar oxygen pressure revealed clustering of nanorods forming a flower-like-structure that has an average length of 2700 nm and an average diameter of 450 nm. The X-ray diffraction spectra show a c-axis orientation of the deposited ZnO with (002) and (110) reflection.