Encontrados 12 documentos, a visualizar página 1 de 2
Pulsed laser deposition of semiconducting nanoparticles : optical emission spec...
Marques, L.; Ramos, Marta M. D.; Gomes, M. J. M.Memory devices that use seminconductor nanocrystals (NC) for charge storage began to receive considerable attention in recent years due to their excellent performance, high capacity of memory and miniaturization. In order to integrate these materials into devices, formation of NCs and oxide layers with controlled stoichiometry, dimensions and homogeneity are required. Pulsed laser deposition (PLD) techniques ar...
Optical emission spectroscopy study of pulsed laser deposition of semiconductin...
Marques, L.; Ramos, Marta M. D.; Gomes, M. J. M.Memory devices that use seminconductor nanocrystals (NC) for charge storage began to receive considerable attention in recent years due to their excellent performance, high capacity of memory and miniaturization. In order to integrate these materials into devices, formation of NCs and oxide layers with controlled stoichiometry, dimensions and homogeneity are required. The optimization of nanoparticle synthesis ...
Controlling the properties of layered self-organized Ge clusters in silica matrix
Pinto, S. R. C.; Roldan, M. A.; Buljan, Maja; Bernstorff, S.; Chahboun, A.; Barradas, N. P.; Alves, E.; Molina, S. I.; Ramos, Marta M. D.Comunicação em poster no simposio M - More than Moore: Novel materials approaches for functionalized Silicon based Microelectronics ; Si and Ge nanocrystals (NCs) embedded in a dielectric matrix, such as SiO2, have attracted great interest for many relevant technological applications. There are many studies about Ge NCs embedded in single layer of SiO2 [1]. However, there are only a few published results about...
Low-temperature fabrication of layered self organized ge clusters by RF-sputtering
Pinto, S. R. C.; Rolo, Anabela G.; Buljan, M.; Chahboun, A.; Bernstorff, S.; Barradas, N. P.; Alves, E.; Kashtiban, R. J.; Bangert, U.; Gomes, M. J. M.In this article, we present an investigation of (Ge + SiO2)/SiO2 multilayers deposited by magnetron sputtering and subsequently annealed at different temperatures. The structural properties were investigated by transmission electron microscopy, grazing incidence small angles X-ray scattering, Rutherford backscattering spectrometry, Raman, and X-ray photoelectron spectroscopies. We show a formation of self-assem...
A microscopy study of germanium nanoparticules produced by pulsed laser deposition
Martín-Sánchez, J.; Marques, L.; Pinto, S. R. C.; Vieira, E. M. F.; Rolo, Anabela G.; Chahboun, A.; Ramos, Marta M. D.; Gomes, M. J. M.Comunicação oral ; Semiconductor nanoparticles (NPs) are of great interest for multiple applications in the fields of photonics, optoelectronics, photovoltaics and biomedicine [1]. The ability to manage properly the size distribution and density in the fabrication process is of crucial relevance. In the literature, it can be found a large number of strategies for NPs production, including physical vapour depos...
Incorporation of CdS nonoparticles from colloidal solution into optically clear...
Boev, Victor I.; Soloviev, A.; Silva, C. J. R.; Gomes, M. J. M.Nanocomposite materials based on an organic-inorganic ureasilicate matrix with embedded CdS nanoparticles were produced and characterized by optical (UV/Vis), FTIR, secondary ion mass spectroscopy, inductively-coupled plasma optical emission and steady-state photoluminescence measurements. The ureasilicate precursor was obtained by the reaction between silicon alkoxyde modified by isocyanate groups and polyethy...
Synthesis and characterization of a sol-gel derived ureasilicate hybrid organic...
Boev, Victor I.; Silva, C. J. R.; Hungerford, Graham; Gomes, M. J. M.A hybrid organic-inorganic material filled with in situ generated inorganic particles has been synthesised by the homogeneous precipitation of CdS from aqueous solutions of Cd(NO3)2 and CH3CSNH2 . These highly transparent, homogeneous and flexible CdS doped xerogels were prepared by the sol-gel technique using, as precursors, organically modified silicon alkoxide (3-isocyanatepropyltriethoxysilane) and a di-ami...
Electrical and photoelectric properties of PZT 65/35 thin films deposited by so...
Boerasu, Iulian; Pintilie, Lucian; Pereira, A. Mário; Vasilevskiy, Mikhail; Gomes, M. J. M.Asymmetric metal–ferroelectric–metal (MFM) structures were manufactured by sol–gel deposition of a lead zirconate-titanate (PZT with Zr/Ti ratio 65/35) film on Pt-coated Si, with a Au top electrode. The average remnant polarization of 9 µC/cm2 and the coercive field of 39 kV/cm were obtained from the hysteresis loop measurements. A detailed analysis of the polarization–electric field (P–E), capacitance–voltage ...
Confined optical vibrations in CdTe quantum dots and clusters
Rolo, Anabela G.; Vasilevskiy, Mikhail; Gaponik, Nikolai; Talapin, Dmitrii; Rogach, Andrey; Gomes, M. J. M.Absorption of far-infrared (FIR) radiation and Raman scattering in CdTe nano-crystals (spherical quantum dots (QDs) of several nanometers in size) and Cd54Te32(SCH2CH2OH)8- 32 clusters prepared by colloidal synthesis were studied. Raman spectra of both QDs and clusters are dominated by a peak situated slightly below the bulk CdTe LO phonon frequency. Experimental FIR transmittance spectra of films containing Cd...
Impact of disorder on optical phonons confined in CdS nano-crystallites embedde...
Vasilevskiy, Mikhail; Rolo, Anabela G.; Gomes, M. J. M.; Vikhrova, Olga; Ricolleau, CristianNon-resonant Raman spectroscopy studies of a set of CdS films annealed at different temperatures were performed and showed a direct correlation between the width of the Raman peak produced by CdS-like optical phonons and the crystalline quality of the semiconductor phase probed by x-ray diffraction (XRD) and transmission electron microscopy (TEM). In order to decribe the Raman lineshape a model proposed by Tral...
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