Showing papers by "Anabela G. Rolo published in 2009"
TL;DR: In this article, structural properties of SiGe quantum dots formed in amorphous silica matrix by magnetron sputtering technique were investigated, and deposition conditions leading to the formation of dense and uniformly sized quantum dots, distributed homogeneously in the matrix.
Abstract: In this paper, we present a study of structural properties of SiGe quantum dots formed in amorphous silica matrix by magnetron sputtering technique. We investigate deposition conditions leading to the formation of dense and uniformly sized quantum dots, distributed homogeneously in the matrix. X-ray and Raman spectroscopy were used to estimate the Si content. A detailed analysis based on grazing incidence small angle x-ray scattering revealed the influence of the deposition conditions on quantum dot sizes, size distributions, spatial arrangement, and concentration of quantum dots in the matrix, as well as the Si:Ge content.
11 citations
TL;DR: In this paper, post-growth annealing effect on CdSe/SiO 2 thin films grown by rf-magnetron co-sputtering technique was investigated.
7 citations
TL;DR: In this paper, CdSe nanocrystals (NCs) embedded in SiO 2 matrix were grown by radio frequency (RF) sputtering technique and X-ray technique was used to characterise the structural properties of the system.
2 citations
TL;DR: X-ray diffraction and Raman scattering patterns confirm that after annealing, doped films keep a polycrystalline nature with (002) preferred orientation and the electrical conductivity increases significantly after the 500 degrees C annealer.
Abstract: In this work we report a study on the structure, optical and electrical properties of P, Sb and Al implanted ZnO thin films that had been produced by r.f. magnetron sputtering. The influence of the different replacing atoms on the structure and properties of the films has been explored. Looking for the best annealing conditions, two different annealing temperatures (300 degrees C and 500 degrees C) have been employed. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction, transmittance and d.c conductivity measurements have been used to characterize the samples. X-ray diffraction and Raman scattering patterns confirm that after annealing, doped films keep a polycrystalline nature with (002) preferred orientation. These films remain very transparent and the electrical conductivity increases significantly after the 500 degrees C annealing, reaching 10.90 (Omegacm)(-1) in the P-doped, 10.33 (Omegacm)(-1) in the Al-doped and 0.56 (Omegacm)(-1) in the Sb-doped samples.
2 citations
TL;DR: In this article, hydrogenated amorphous and nanocrystalline silicon thin films were implanted with erbium-implanted wires and measured photoluminescence (PL) activity at 1.54 µm, with an FWHM of 5 nm.
Abstract: Hydrogenated amorphous and nanocrystalline silicon thin films deposited by hot wire (HW) and radio-frequency plasma-enhanced chemical vapour deposition (RF-PECVD) were erbium-implanted. Their pre-implantation structural properties and post-implantation optical properties were studied and correlated. After 1 h annealing at 150 °C in nitrogen atmosphere only amorphous films showed photoluminescence (PL) activity at 1.54 measured at 5 K. After further annealing at 300 °C for 1 h, all the samples exhibited a sharp PL peak positioned at 1.54 μm, with an FWHM of ~5 nm. Amorphous films deposited by HW originated a stronger PL peak than corresponding films deposited by RF, while in nanocrystalline films PL emission was much stronger in samples deposited by RF than by HW. There was no noticeable difference in Er 3+ PL activity between films implanted with 1 × 10 14 and 5 x 10 15 atoms cm -2 Er doses.