Optical Characterization of Thick Films for Some Oxides Fabricated by Pulsed Laser Deposition

Abstract

The main aim of this study was to deposit thick films of Titanium dioxide, Zinc oxide and Aluminum oxide, all deposited individually on a glass substrate by pulsed laser technique . In this technique a Q-Switch Nd:YAG laser with wavelength 1064 nm, pulse energy 500, 600, and 700 mJ, respectively, was used. The repetition rate was 20, 30 and 40Hz. In the beginning of the process, disks of these oxides were fabricated via mixing with Potassium Bromide of equal weight ratios: 50% - 50% for all oxides. In order to make these disks, the materials were compressed via a compressor of high pressure. Laser beam of pulse energy 500mJ and10ns pulse duration with frequency of20Hz,was focused on Titanium dioxide disk and plasma was obtained from each disk and deposited on the glass substrate. The former procedure was repeated with increasing repetition rate to (30) Hz then (40) Hz. Afterward, the same above procedure was repeated by increasing the laser pulse energy to (600 mJ), then to (700 mJ). All above mentioned steps were repeated with ZnO and Al2O3 disks. The thickness of each film was measured by the scanning electron microscope, and the relation between the film thickness and the repletion rate for each energy of the pulsed laser was plotted. The measurements of the transmitted intensity for some lasers were carried out from which the refractive indices, absorption coefficients were calculated, the transmission percentage for each film was measured too, Consequently, the relations between the refractive indices and absorption coefficients with wavelength were plotted. Same steps were repeated for all films. A comparison was done between the optical properties (transmission spectrum, refractive indices and absorption) of the films, where it was noticed that these optical properties depend on the thickness of the thick film. v Results revealed that it is possible to use these films of filters at at certain wavelengths, or reflectors for other wavelengths. Finally future work were recommended.