Further insight into the growth temperature influence of 1.3 μm GaInNAs/GaAs QWs on their properties

Abstract

The authors further investigate the influence of growth temperature (Tg) on GaInNAs QWs grown on GaAs. 7 nm-thick GaInNAs QWs were grown with Tg in the range 400–470 °C. As a first result, transmission electron microscopy clearly showed that flat interfaces are obtained for Tg lower than 450 °C. Beyond this temperature, the upper interface of the QW starts to undulate. Then the series of QWs was annealed at different temperatures. The PL emission of the QWs was blue-shifted and narrowed. However, it was noticed that these evolutions occurred at a lower annealing temperature (Ta) when a lower Tg was used for the growth. Even though the PL energies of the different as-grown QWs were the same, this observation tends to show that the nanotexture of the GaInNAs alloys depends on Tg in the range of temperatures investigated. The texture obtained at low Tg is more easily rearranged, by annealing, into a more stable configuration. This result is of practical importance for the growth of GaInNAs QW laser structures. By using the lowest Tg for the GaInNAs QWs, the AlGaAs cladding layer growth temperature (usually around 620 °C) is high enough to optimise the QW quality by its annealing effect.