Fabrication techniques and material properties of dielectric MgO thin films—A status review

During the past few decades, considerable research effort has been directed towards the development of fundamental peculiarities of wide-gap (Eg > 5 eV) inorganic dielectric thin films. Wide-gap dielectrics are used for various technical and technological applications as laser materials, electronic components, radiation resistant materials, spectral transformers for luminescent lamps, detectors and dosimeters of several kind of radiations, various sensors and catalytic agents. The optical characteristics of intrinsic electronic excitations in inorganic wide-gap dielectric are shifted towards the vacuum ultra-violet spectral region and therefore being studied insufficiently that impedes the elaboration of new materials and the modernization of the existing ones based on wide-gap dielectrics. Besides, alkali halides, the value of energy band gap Eg >6 eV is typical of numerous wide-gap oxides: MgO, CaO, Al2O3, SiO2, Y2O3, etc. Among this, magnesia (MgO) is a well-known refractory oxide, has the potential advantages of a wide band gap (Eg ∼ 7.8 eV) and is predominantly preferred to be used as lattice templates for growing oriented ferroelectric and superconducting over layers because of its higher Poisson's ratio and lower Gibb's free energy. Well-defined procedures to prepare MgO surfaces of very high quality is of importance in a number of areas of surface physics and imperfect due to their preparation kinetics, inclusion of foreign matter and compositional variations. Even though, increasing number of researchers, laboratories have engaged in the fabrication and characterization of MgO because of its excellent scientifically based applications. The scope of this review article is to summarize briefly the important research achievements on higher quality MgO thin films with novel physical properties and systematic interrelationship for fabrication conditions, crystal structure, composition predictions, surface morphology, electrical and optical characterizations. Particular attention is given to the secondary electron emission coefficient of the fabricated film due to their applications in the alternating current plasma display panel as a protecting layer of dielectrics to improve the discharge characteristics and the panel's lifetime.