Density functional investigation of structural, electronic, optical and thermodynamic properties of Zn1−x Be x O semiconductor

Based on the first principles calculations using a full potential linearized augmented plane wave (FP-LAPW) method in the modified Becke–Johnson (mBJ) approximation, we calculated the electronic, optical and thermodynamic properties of Zn1-xBexO for different Be concentrations (0≤x≤1). The calculated structure of Zn1-xBexO for x=0.25,x=0.5andx=0.75 was changed compared to the end structures (x=0andx=1) and passed from wurtzite to orthorhombic structures, while most of the previous works show that the structures of ZnO remained unchanged after doping with Be. Our result shows that the orthorhombic lattices have lower formation energies than wurtzite. The calculated band structures show an increase in energy bandgap with increasing Be concentrations and present a gap bowing close to 10 eV. The electronic structure was studied by oxygen k-edge X-ray emission (XES) and X-ray absorption (XAS). Moreover, the calculated absorption coefficient indicates that the Zn1-xBexO exhibit more interesting properties in UV region main absorption. The thermodynamic stability of these compounds has also been well studied and confirms well the previous experimental results. The calculations show that if the Be doping quantity increases, the doping system absorption spectrum blueshift becomes more significant, the energy loss peak moves towards the direction of high energy and the plasmon frequency ωp become stronger in the case of BeO.