Relation between hole density and impurity density in ZnMgSSe semiconductors

Using amphoteric native defect model [Walukiewicz, Phys. Rev. B 37, 4760 (1988)], we have considered the energy-gap Eg dependence of nitrogen doping in ZnMgSSe semiconductors. We have explained the energy-gap Eg dependence of saturated hole concentration in ZnMgSSe semiconductors based on the amphoteric native defect model and available effective hole masses in ZnSe using the valence band discontinuity ΔEv as a fitting parameter. The Fermi-level stabilization energy EFS and the pinned Fermi-level energy ESI are, to a good approximation, universal for II-VI materials as well as for III-V materials. We have estimated the ESI is located at 1.895 eV below EFS. It is indicated that the band-gap discontinuity between ZnSe and ZnMgSSe is ΔEc: ΔEv=0.55:0.45 if effective hole mass is 1.4 m0 for ZnMgSSe and ΔEc:ΔEv=0.67:0.33 if effective hole mass is 0.6 m0.