Evaluation of implantation-disordering of (InGa)As/GaAs strained-layer superlattices

We have examined the optical and transport properties of In02Ga08As/GaAs strained-layer superlattices (SLS's) which have been implanted either with 5 x 1015/cm2, 250 keV Zn+ or with 5 x 1014/cm2, 70 keV Be+ and annealed under an arsenic overpressure at 6000C. For both cases, electrical activation in the implantation-doped regions equalled that of similar implants and anneals in bulk GaAs, even though the Be implant retained the SLS structure, while the Zn implant intermixed the SLS layers to produce an alloy semiconductor of the average SLS composition. Photoluminescence intensities in the annealed implanted regions were significantly reduced from that of virgin material, apparently due to residual implant damage. Diodes formed from both the Be- and the Zn-implanted SLS's produced electroluminescence intensity comparable to that of grown-junction SLS diodes in the same chemical system, despite the implantation processing and the potential for vertical lattice mismatch in the Zn-disordered SLS device. These results indicate that Zn-disordering can be as useful for strained-layer superlattices as in lattice-matched systems