0000000000146726
AUTHOR
Gilles Patriarche
Structural studies of nano/micrometric semiconducting GaInP wires grown by MOCVD
Abstract 3D (Ga,In)/GaInP structures were grown on polycrystalline InP substrates by the MOCVD technique. The growth temperature was varied from 600 to 700 °C. Trimethyl-gallium and N 2 were, respectively, used as the Ga source and the carrier gas. These newly presented 3D structures have a scepter-like shape and are composed of a long GaInP internal support (rods of tens of μm long and tens of nm diameter) capped by a micrometer size metallic (Ga,In) structure. These structures were characterized by the SEM, EDX and TEM techniques. High-resolution TEM shows that the support rods present a GaInP single crystal structure. A preliminary discussion about the growth step mechanism, based on the…
Growth of nanometric CuGaxOystructures on copper substrates
This paper presents an alternative method based on the metal–organic chemical vapour deposition technique to obtain new nanowire structures. Here, the metal–organic precursor acts as a catalyst and interacts with a metallic substrate to produce 3D structures such as nanowires. In the present case, trimethyl gallium interacts with a copper metallic substrate to build a single-crystalline CuGaxOy wire structure. Electronic microscopy techniques on image or diffraction modes have provided the structural and chemical characterization of the obtained nanowires.
Photo-Activated Phosphorescence of Ultrafine ZnS:Mn Quantum Dots: On the Lattice Strain Contribution
We address the enhancement of orange-light luminescence of Mn-doped zinc sulfide nanoparticles (NPs) induced by exposure to UV light. Ultrafine ZnS:Mn NPs are prepared by microwave-assisted crystal growth in ethanol, without adding any dispersant agents. When exposed to UV light, their orange emission intensity undergoes a strong increase. This effect is observed when the NPs are deposited as a thin layer on a transparent substrate or dispersed in an ethanolic suspension. Such a feature was already observed on polymer- or surfactant-coated ZnS:Mn NPs and explained as a passivation effect. In this study, by coupling X-ray photoelectron, Fourier transform infrared, and electron paramagnetic r…
Vapor-liquid-solid mechanisms: Challenges for nanosized quantum cluster/dot/wire materials
International audience; The growth mechanism model of a nanoscaled material is a critical step that has to be refined for a better understanding of a nanostructure's dot/wire fabrication. To do so, the growth mechanism will be discussed in this paper and the influence of the size of the metallic nanocluster starting point, referred to later as “size effect,” will be studied. Among many of the so-called size effects, a tremendous decrease of the melting point of the metallic nanocluster changes the physical properties as well as the physical/mechanical interactions inside the growing structure composed of a metallic dot on top of a column. The thermodynamic size effect is related to the bend…