Below bandgap emission and absorption in ZnSnP2/GaAs heterojunctions

Below bandgap emission and absorption are observed in p-ZnSnP
2
on n-GaAs heterojunctions. The band lineup of this heterostructure system suggests that the below bandgap transition is between the valence bands of GaAs and the conduction band of ZnSnP
2
at the interface. The predicted value for the interfacial gap of
E_{I} = 1.27
eV compares with an experimental value of 1.31 eV.