Orientation Effect in GaAs Injection Lasers

An orientation effect was found with regard to the emission patterns observed on GaAs injection lasers. The emission in the [11̄0] direction is considerably more uniform than that in the [110] direction. The beadiness observed on the (110) plane is believed to be due to linear low-resistivity regions parallel to [110]. These result from zinc decoration of the misfit dislocations parallel to [110]. The absence of zinc decoration on the [11̄0] set of misfit dislocations can explain the absence of local bright spots and, thus, the more uniform emission in this direction.