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Vertical-cavity lasers emitting at 1.3 /spl mu/m are extremely attractive for high bandwidth fiber communications where it is advantageous to operate at the dispersion minimum of silica optical fiber. To date, VCSELs based on pseudomorphic GaAs materials have achieved lasing emission only slightly longer than 1.3 /spl mu/m. We report the first 1.3 /spl mu/m selectively oxidized VCSELs using InGaAsN quantum wells which operate at continuous wave at and above room temperature.

Plasma hydrogenation has recently been demonstrated to be highly effective in passivating dislocations in heteroepitaxial InP and is a promising technique for achieving viable heteroepitaxial InP solar cells. In this paper, the effects of hydrogen on the fundamental properties of three dislocation related hole traps in heteroepitaxial InP/GaAs are presented. Hydrogen passivation significantly alters the dislocation trapping kinetics, causing point defect-like behavior consistent with a transformation from dislocation-related defect bands within the InP bandgap to a low concentration of individual deep levels after hydrogenation. Furthermore, hydrogen passivation is shown to shift the dominant space charge generation center from E/sub c/-0.71 eV to E/sub c/-0.92 eV, away from midgap. A model is proposed which explains these effects on the basis of decreased electronic interaction between dislocation sites. Finally, a comparison of InP material quality grown on GaAs, Ge and GaAs/Ge substrates is presented, and hydrogen passivation of InP/GaAs/Ge structures is reported.

Elimination of anti-phase domains (APDs), threading dislocations and uncontrolled interface diffusion are critical considerations for achieving maximum design flexibility and high efficiency in multi-bandgap III-V solar cells on Ge. In this paper, we identify critical growth steps to eliminate each of these problems and present an optimum molecular beam epitaxy (MBE) growth procedure which yields APD-free, near-dislocation-free GaAs/Ge with greatly suppressed interdiffusion in both the GaAs overlayer and Ge substrate. For solid source MBE, elimination of APDs requires a double-stepped, clean Ge surface and a prelayer consisting of a complete monolayer of either As or Ga. Correct conditions can be observed and maintained by real-time in-situ monitoring to ensure reproducibility. Initiating growth at low temperature with migration enhanced epitaxy virtually eliminates Ge diffusion into GaAs and Ga diffusion into Ge, while As diffusion into Ge is substantially suppressed.