We have studied nanostructured samples of InAs/InP(001) by means of Grazing Incidence Diffraction Anomalous Fine Structure. The samples, grown by molecular beam epitaxy, show a periodic corrugation on the surface giving rise to an array of self-assembled quantum wires after deposition of 2.5 monolayers of InAs. We measured the (440) and (420) GIDAFS spectra, at the As K-edge, at incidence and outgoing angles close to the substrate's critical angle. We analysed the anomalous diffraction lineshapes vs. the energy, as well as the oscillatory part of the signal in the extended region above the edge and obtained, for the first time, information about composition and strain inside the quantum wires and close to the interface. Our results suggest possible interfaces.

We acknowledge the French CRG-BM02 (D2AM) and the Italian CRG-BM08 (GILDA) beamlines for granting beam time and for technical assistance. We are grateful to Drs. F. D’Acapito and A. Mazuelas for helpful discussions. One of the authors (MGP) is pleased to acknowledge support from the “Université Joseph Fourier” of Grenoble and the “Centre National pour la Recherche Scientifique” for visits during which the research was completed. This work was also supported by the LEA-MANES European Agreement and by CICYT project No. MAT99-0847.

7 páginas, 5 figuras, 1 tabla.-- PACS: 61.10.-i – X-ray diffraction and scattering. 61.10.Ht – X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc. 68.65.-k – Low-dimensional, mesoscopic, and nanoscale systems: structure and nonelectronic properties.

Peer reviewed