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We have investigated the compositional modulation of AlGaAs layers grown in tetrahedral-shaped recesses (TSRs) on n-type GaAs (111)B substrates using scanning electron microscopy, photoluminescence and cathodoluminescence. Growth hardly occurred between the TSRs, and complicated facets were seen in the TSR. Gallium-rich regions were formed around the edges between sidewalls rather than at the center of sidewalls and at the bottom region rather than the top region. To observe the facetting process during growth, GaAs/AlGaAs multilayers were also grown in TSRs. Aluminum compositional modulation is dependent not only on the difference in migration distances of Ga and Al atoms but also on the differences in the incorporating process among different facets.

The KrF laser ablation of Al, Cu, Si, and SrTiO3 targets has been studied using an electrostatic deflection energy analyzer and a quadrupole mass filter. Beam like ions appear to accompany ablation. The average kinetic energies of Si+ and metal ions are about 45 eV and 60 eV, respectively. The energies of ions are ranked in the order of Si3. The mean ion energy of Cu+ is not affected by the laser fluence range of 2-7.5 J/cm2.