Substrate Dependence of the Properties of MgO Films Produced Using an Aqueous Chemical Growth Method

Muhammad      Azmi Abdul Hamid; Maria      Abu Bakar; Azman      Jalar; Roslinda      Shamsudin

doi:10.2174/1573413711208010050

Abstract

Using a simple solution route based on the reaction between magnesium tetrahydrate ((CH3COO)2Mg.4H2O)) and hexamethylenetetramine (C6H12N4), MgO films were grown on Mg and MgO. Morphological observations revealed that porous MgO films were obtained on Mg, while sheet-like films were produced when MgO was used as the substrate. The EDX results indicated that only Mg and O were present in all of the films. When Mg was used as the substrate, the resistivity of the MgO film decreased from 2.060 x 102 Ω cm to 1.990 x 102 Ω cm as the temperature was increased to 150° C. In contrast, the resistivity decreased to 1.820 x 102 Ω cm when MgO was used as the substrate at 150° C. The morphology and crystallinity of the material likely played a role in the reduced resistivity of the films. The bandgap of MgO films was dependent on the type of substrate and the reaction temperature. The bandgap of MgO films grown on Mg increased from 5.18 eV to 5.27 eV as the temperature increased from 90° C to 150° C. A similar increase was also observed when a film of MgO was grown on MgO. However, the bandgap energies obtained in this study were well below that of bulk MgO due to the non-stoichiometry of the deposited layers and crystallinity of the samples, as shown by EDX and XRD, respectively.

Keywords: Aqueous chemical growth, MgO film, Optical properties, Porous-like, Resistivity, Sheet-like, morphology, crystallinit