Synthesis of MgO thin films: How heat treatment affects their structural, electro-optical, and surface properties

Abstract

In this study, MgO thin films were grown using Chemical Bath Deposition (CBD) and annealed at various temperatures (300, 350, 400, and 450°C). Their structural properties were obtained by X-ray diffraction (XRD), and amorphous MgO structures were observed in the XRD pattern. EDX composition analysis showed that the amount of Mg increased with temperature, and so did oxidation. Surface morphologies and surface roughness were analyzed by FESEM and AFM. The amorphous structures were in the form of a sugar cube at 300°C and turned into a homogeneous nanorod-like structure as the temperature increased to 400-450°C. Current-voltage (I-V) measurements were taken with a Keithley 2400 sourcemeter, and electrical resistivity was calculated using film thickness. The increase in surface roughness created a resistance effect in transmission, reducing the charge storage capacity. The transmittance (T), reflectance (R), refractive index (n), and damping coefficient (k) were determined via a UV-vis spectrophotometer. E g values of MgO thin films tempered at 300, 350, 400, and 450°C were 3.85, 3.98, 3.87, and 4.08eV, respectively.