Strain relaxation in rapid thermally annealed InAs/GaAs quantum dot infrared photodetectors

In this paper the effect of rapid thermal annealing (RTA) on a 30 stacked InAs/GaAs, molecular beam epitaxially grown quantum dot infrared detector (QDIP) device is studied. Temperatures in the range of 700 - 900/spl deg/C for 60 s, typical of ion implantation induced interdiffusion, are used. Double crystal X-ray diffraction (DCXRD), photoluminescence (PL), cross sectional transmission electron microscopy (XTEM) and device electrical characteristics were used to monitor changes due to RTA. The QDIP devices had good PL signal which improved upon annealing. However the device performance after RTA was poor and DCXRD and XTEM results clearly indicate that strain relaxation is occurring. The role of strain relaxation on optical and electrical properties has been discussed.