Near-field luminescence measurements on GaInAsP/InP double heterostructures at room temperature

Spatially resolved near-field luminescence spectroscopy was carried out on locally grown InP ridges, overgrown by a GaInAsP layer in metal organic molecular beam epitaxy. For free access to the quaternary layer the cleaved surface was investigated. Two different reflection scanning near-field microscopy setups were used. In the illumination mode we were able to estimate the charge-carrier diffusion in the InP. For improving the spatial resolution, measurements were also carried out in the collection mode. Here a shift of the center wavelength toward lower energy occurs near the side facets. This can be a result of a material composition gradient or of strained growth near the side facets. A second recombination channel at 1115 nm occurs at the growth-nongrowth transition. With the simultaneous recorded topography this recombination channel can be localized in the quaternary layer grown on the side of the InP ridge.