Electronic structures of wurtzite ZnO, BeO, MgO and p-type doping in Zn1−xYxO (Y = Mg, Be)

Abstract

Using the density function theory within the generalized gradient approximation, the band structures of wurtzite ZnO, BeO and MgO have been calculated. The effective-mass parameters are fitted using the calculated eigenvalues. The Dresselhaus spin–orbit effect appears in the k[100] direction, and is zero in the high symmetry direction k[001]. The orderings of valence band split by the crystal-field and spin–orbit coupling in wurtzite ZnO, BeO and MgO are identified by analyzing the wave function characters calculated by projecting the wave functions onto p-state in the spherical harmonics. For wurtzite ZnO, the ordering of valence band is still Γ7>Γ9>Γ7 due to the negative spin–orbit coupling splitting energy and the positive crystal-field splitting energy. Thus, the Thomas’ conclusion is confirmed. For wurtzite BeO and MgO, although their orderings of valence bands are Γ7>Γ9>Γ7 too, the origins of their orderings are different from that of wurtzite ZnO. Zn1−xYxO (Y=Mg, Be) doped with N and P atoms have been studied using first-principles method. The calculated results show that N atom doped in Zn1−xBexO has more shallow acceptor energy level with increasing the concentration of Be atom.