Structures and electronic properties of misfit dislocations in ZnSe/GaAs(001) heterojunctions

The structures and electronic properties of misfit dislocations in ZnSe/GaAs(001) heterojunctions have been studied by transmission electron microscopy, cathodoluminescence (CL), and photoluminescence. In undoped ZnSe epilayers, irregular dislocation segments tending to lie roughly along [100] and [010] directions were observed as well as long straight 60° dislocations along [110] and [11̄0] directions. In N-doped ([N]≳1×1018 cm−3) ZnSe epilayers, the misfit dislocations were predominantly dissociated into partial dislocations which makes cross slip and formation of irregular dislocations more difficult; only the straight dislocations along [110] and [11̄0] were observed. The CL observations suggest that the irregular dislocations trap carriers more efficiently than the dislocations along 〈110〉.