Fernando Briones

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We have studied the influence of InP buffer-layer morphology in the formation of InAs nanostructures grown on InP~001! substrates by solid-source molecular-beam epitaxy. Our results demonstrate that when InP buffer layers are grown by atomic-layer molecular-beam epitaxy, InAs quantum dot-like structures are formed, whereas InP buffer layers grown by MBE(More)
The magnetic properties of the system MnZnO prepared by conventional ceramic procedures using ZnO and MnO(2) starting powders are studied and related to the nanostructure. Thermal treatment at 500 °C produces a ferromagnetic phase, although this temperature is not high enough to promote proper sintering; thus the thermally treated compact shows brittle(More)
In this paper we present the Raman scattering of self-assembled InSb dots grown on ~001! oriented InP substrates. The samples were grown by pulsed molecular beam epitaxy mode. Two types of samples have been investigated. In one type the InSb dots were capped with 200 monolayers of InP; in the other type no capping was deposited after the InSb dot formation.(More)
The increasing use of biofunctionalized magnetic nanoparticles in biomedical applications calls for further development of characterization tools that allow for determining the interactions of the nanoparticles with the biological medium in situ. In cell-incubating conditions, for example, nanoparticles may aggregate and serum proteins adsorb on the(More)
The development of sensitive and easy-to-use biosensors that allow an adequate characterization of specific weak biological interactions like carbohydrate-lectin interactions still remains challenging today. Nanoparticles functionalized with carbohydrates are one of the most powerful systems for studying carbohydrate-lectin interactions, because they mimic(More)
The sticking effect between hydrophilic surfaces occurring at increasing relative humidity (RH) is an everyday phenomenon with uncountable implications. Here experimental evidence is presented for a counterintuitive monotonous decrease of the capillary adhesion forces between hydrophilic surfaces with increasing RH for the whole humidity range. It is shown(More)
In segregation effects during InAs growth on GaAs~001! and critical thickness for InAs self-assembled quantum dots are studied using a real time, in situ technique capable of measuring accumulated stress during growth. Due to a large (;50%) surface In segregation of floating In, self-assembled dot formation takes place when less than one monolayer of InAs(More)
We present a fabrication method to produce site-controlled and regularly spaced InAs/GaAs quantum dots for applications in quantum optical information devices. The high selectivity of our epitaxial regrowth procedure can be used to allocate the quantum dots only in positions predefined by ex-situ local oxidation atomic force nanolithography. The quantum(More)
In this Letter, we experimentally show that the room temperature ferromagnetism in the Mn-Zn-O system recently observed is associated with the coexistence of Mn(3+) and Mn(4+) via a double-exchange mechanism. The presence of the ZnO around MnO(2) modifies the kinetics of MnO(2)-->Mn(2)O(3) reduction and favors the coexistence of both Mn oxidation states.(More)
Magneto-optic ~MO! experimental and computational studies are reported on arrays of epitaxial Fe~001! microsquares. Measuring the transverse Kerr signal, in both reflected and diffracted spots, when the array is exposed to a rotating magnetic field allows the quantification of the magnetization inhomogeneties within the microsquares. The MO signal at(More)