InAs quantum dots (QDs) overgrown by a Ga0.85In0.15NxAs1−x (0⩽x⩽0.017) layer have been realized on GaAs substrate by molecular beam epitaxy. When the nitrogen composition increases, the photoluminescence (PL) wavelength redshifts up to 1.52μm. It is shown that PL properties of InAs∕Ga0.85In0.15N0.012As0.988 QDs are improved by thermal annealing. Finally, 1.45μm PL emission with a 38.5meV full width at half maximum is obtained at room temperature.

Surface extended-x-ray-absorption fine structure (SEXAFS) has been combined with scanning tunneling microscopy (STM) to determine both the local and long-range bonding properties of the Si(001)2x l-Sb interface. Sb L3 edge SEXAFS shows that Sb dimers occupy a modified bridge site on the Si (001) surface with a Sb-Sb near-neighbor distance of 2.88 ±0.03 A. Each Sb atom of the dimer is bonded to two Si atoms with a Sb-Si bond length of 2.63 ± 0.04 A. STM resolves the dimer structure and provides the long-range periodicity of the surface. Low-energy-electron diffraction of vicinal Si(OOl) shows that the Sb dimer chains run perpendicular to the original Si dimer chains.