N2-incorporation-induced blue shift in InGaAsN/GaAs quantum well during annealing

Three different kinds of quantum wells (QWs) were grown at the same growth temperature by molecular beam epitaxy (MBE): InGaAs/GaAs QW without any N₂ background; InGaAs(N₂)/GaAs double QWs with N₂ flow to the sample but without plasma; and InGaAsN/GaAs QW with N-plasma. The latter two types of QW were grown on one sample. Post-growth rapid thermal annealing (RTA) was applied to them at 700°C. After 31.5 min of RTA, it was observed that the photoluminescence blue shift of the InGaAs(N₂) QW was 40 meV, which was 9 meV more than that for the InGaAsN QW, and the InGaAs QW had only about 13 meV blue shift. However, for the as-grown case, the PL peak position of the InGaAs QW and InGaAs(N₂) QWs were the same (1148 nm), and for the InGaAsN QW it was 220 nm longer. This indicates that there is N₂ incorporation during InGaAsN growth, the N₂ incorporation does not affect the band structure and the N₂ incorporation dominates the blue shift during RTA.