Some physical properties of thin MgO films produced by reactive evaporation

Films of magnesium oxide were deposited by reactive evaporation using an electron gun. The films were polycrystalline with a preferential 1 1 1 orientation when their thickness was greater than 2m. Based on the transmission coefficient in the visible and ultraviolet range, the optical gap was calculated to be E _g=4.3 eV. The a.c. and d.c. electrical properties were evaluated using a single model: conduction by electron hopping from a trap level to extended states in the conduction band. The ionization energy of this trap level, which was clearly due to oxygen vacancies, was E _i=(1.4±0.1) eV.