Role of buffer surface morphology and alloying effects on the properties of InAs nanostructures grown on InP(001)

International audienceWe show the role played by the buffer surface morphology and by alloying effects on the size, shape and lateral distribution of InAs nanostructures grown on InP001 substrates by molecular beam epitaxy. Three buffers, viz., In 0.53 Ga 0.47 As, In 0.52 Al 0.48 As, and InP lattice matched on InP have been studied. Differences in nanostructure morphology and in carrier confinement have been evaluated by atomic force microscopy and by low-temperature photoluminescence measurements, respectively. Alongside the classical relaxation mode through two-dimensional/three-dimensional surface morphology change, a chemical relaxation mode has to be introduced as a competitive mode of relaxation of strained layers. This chemical relaxation mode, due to alloying between the InAs deposit and the buffer, is thought to be responsible for most of the observed differences in the InAs nanostructure properties

Surface effects on shape, self-organization and photoluminescence of InAs islands grown on InAlAs/InP(001)

International audienceInAs nanostructures were grown on In 0.52 Al 0.48 As alloy lattice matched on InP001 substrates by molecular beam epitaxy using specific growth parameters in order to improve island self-organization. We show how the change in InAs surface reconstruction via growth temperature from (24) to (21) and/or the use of InAlAs initial buffer surface treatments improve the island shape homogeneity either as quantum wires or as quantum dots. Differences in island shape and in carrier confinement are shown by atomic force microscopy and by photoluminescence measurements, respectively. We point out that such shape amendments induce drastic improvements to island size distribution and discernible changes in photoluminescence properties, in particular concerning polarization

Observation of photoluminescence from InAs surface quantum wells grown on InP(100) by molecular beam epitaxy

Photoluminescence (PL) measurements are presented for thin epitaxial layers of InAs, 2.5 Å<d <36 Å, grown on InP(100) by molecular beam epitaxy. The combination of efficient carrier capture and PL redshift with increasing InAs thickness clearly indicate the formation of InAs quantum wells on the InP surface. Data are also presented for InAs/InP structures capped with strained layers of either GaAs or In0.5 Al0.5 As. Since radiative recombination within the InAs layers can be distinguished from PL arising from both bulk and surface defects, this system allows us to monitor the quality of both the InAs/InP and InAs/air interfaces via their influence on the InAs quantum well luminescence

THE TUNABLE VIBRONIC LASER MATERIALS BASED ON TRANSITION METAL IONS : SEARCH OF NEW SYSTEMS AND EXCITED STATE SPECTROSCOPY

For they are stable and they allow to get intense and tunable radiations in a large spectral domain, the vibronic solid state laser materials based on transition metal ions such as Ti3+, Cr3+, V2+, Ni2+ and Co2+ give rise presently to a renewed and increased interest, and more particularly in our laboratory as concerns the optical studies

Photoluminescence excitation spectroscopy of Ti 3+ in GaP

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Photoluminescence temperature and polarisation dependant studies of InAs quantum dots grown on InP(001) by MBE

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