Pulsed laser deposition of nanostructured MgO film: effect of laser fluence on the structural and optical properties

Abstract

We report the preparation of nanostructured MgO films by pulsed laser deposition technique at a substrate temperature of 100 °C. The effect of laser fluence on the structural, morphological and optical properties of MgO nanostructure was studied. XRD results show the MgO thin films were polycrystalline in nature with cubic structure. The film thickness of the deposited film increases as laser fluence increase. The direct optical energy gap of MgO films was in the range of (4.6–5.2) eV depending on the laser fluence. The values of measured penetration depth as a function of laser fluence are compared with the calculated values. The root mean square of surface roughness of the film increases with increasing the laser fluence. The SEM investigation confirms the particle size of deposited MgO was in the range of (8.4–30.5) nm and the density and size of the droplets and particulates was found to be increased with laser fluence. The particle size distribution was strongly dependent on the laser fluence. The EDX analysis shows that the grown MgO film shows the presence of peaks related to magnesium and oxygen elements and the sample prepared at 4.3 J cm−2 was stoichiometric, while the other films exhibit a small-off stoichiometric.