Electronic structure and electrical conductivity of MgO protecting layer in plasma-display panels: A tight-binding quantum chemical study

The tight-binding quantum chemical molecular dynamics code, Colors, has been successfully applied to the electronic-structure calculations of the MgO-protecting-layer model in plasmadisplay panels (PDPs). The code succeeded in reproducing the band-gap energy of the MgO crystal structure. The energy gap between the bottom of the conduction band (CB) and the top of valence band (VB) was 7.45 eV, which is in quantitative agreement with the experimental and previous theoretical results. The electronic structure of the undoped MgO model and Si-doped MgO model was also calculated. The impurity level was 2.15 eV lower than that for the bottom of the CB. This result was in qualitative agreement with recent cathodoluminescence measurements. In addition, we have already succeeded in developing a novel electrical conductivity simulator using the spatial distribution of the probability density of wave functions obtained from the tight-binding quantum chemical molecular dynamics code, Colors. The electrical conductivity of the MgO-protecting-layer model was estimated with and without an oxygen defect and a significant change in the electrical conductivity of the MgO-protecting-layer materials was observed with the introduction of oxygen defects.