Valence Offsets of Three Series of Alloy Heterojunctions

Electron structure of three series of alloy heterojunctions (GaAs)_x(Ge₂)_1-x/Ge,(AlAs)_x (Ge₂)_1-x/Ge and Al_xG_1-xAs/Ge are calculated by linear muffin-tin orbital method with atomic-sphere approximation using the average-bond-energy theory in conjunction with a cluster expansion method. The results indicate the variations of ΔE_v(x) at heterojunctions (GeAs)_x(Ge₂)_1-x/Ge and (AlAs)_x (Ge₂)_1-x/Ge are nonlinear, which are very different from that of Al_xGa_1-xAs/Ge.