Photoluminescence of a GaAs/Al0.3Ga0.7As near-surface quantum well structure was used to study the quality of the interface between GaAs and GaS deposited in ultra-high vacuum. In addition to the luminescence of the near-surface and the deep/reference quantum wells, luminescence was observed for the GaAs cap following the deposition of 100Å of GaS. This additional feature demonstrated the high quality GaS/GaAs interface achievable through the ultra-high vacuum deposition of this precursor. The ratios of the integrated luminescence intensity of both the GaAs cap and the near-surface GaAs quantum well to the deep/reference quantum well indicate that there were fewer GaS/GaAs interface states for deposition on the Ga-rich GaAs(001)-(4 x 2)/(2 x 6) surface compared to deposition on the As-rich GaAs(001)-(2 x 4) surface. Furthermore, GaS passivated samples exposed to ambient conditions for eight months exhibited no luminescence degradation for the near-surface quantum well confirming that these films provide adequate passivation longevity.

Effect of Initial Surface Reconstruction on the GaS/GaAs(001) Interface. R.I.Pelzel, B.Z.Nosho, W.V.Shoenfeld, T.Lundstrom, P.M.Petroff, W.H.Weinberg: Applied Physics Letters, 1999, 75[21], 3354