Material localisation at GaInAsP-ridge-structures selectively grown by MOMBE

GaInAsP-ridges with vertical side-walls can be achieved by metalorganic mol ecular beam epitaxy (MOMBE) when using substrates with misorientated surfac es. The anisotropic surface diffusion of group III growth species leads to a different material composition at these side walls and at the transition( 1 1 1) facets. Spatially resolved measurements show a second recombination signal at lower energies in addition to the recoInbination on the top of th e ridge. The behaviour of the intensity and the energy offset compared to t he recombination originated from the ridge centre has been investigated for different material compositions. For that purpose, selectively grown InP r idge structures have been overgrown with quaternary GaInAsP (lambda(g) = 95 0 to 1550 nm) and ternary GaInAs layers. Both energy confinement and recomb ination intensity of the side facet recombination signal show a maximum (De lta E-g,E-max = 111 meV) at nominal material composition with wavelengths b etween 1050 and 1250 nm. The effect of group III alkyl prereactions on the growth will be discussed for application to low-dimensional structures. (C) 1998 Elsevier Science B.V. All rights reserved.