Naslov
Ion beam synthesis and characterization of Ge nanocrystals in SiO2

Autori
Desnica, Uroš ; Buljan, Maja ; Dubček, Pavo ; Siketić, Zdravko ; Bogdanović Radović, Ivančica ; Bernstorff, S. ; Serincan, U. ; Turan, R.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Abstracts of the 17th International Conference on Ion Beam Analysis : IBA 2005 / - Sevilla : CNA, CMAM, 2005

Skup
17th International Conference on Ion Beam Analysis : IBA 2005

Mjesto i datum
Sevilla, Španjolska, 26.06.2005. - 01.07.2005

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
ion beam; Ge ions

Sažetak
Ge quantum dots (QD) embedded in transparent matrix exhibit intense photo- and electro-luminescence, strong third-order optical nonlinearities and tunable absorption - all strongly dependent on QDs size. This makes them potentially suitable for electronic, optoelectronic and photonic applications. Ge QDs have been obtained by implanting 100 keV 74Ge ions into SiO2. Ion doses varied from 1016/cm2-1017/cm2, postimplantation annealing temperature, Ta, from 300 to 1000 oC, and annealing time, ta, from 0.3 to 9 hours. The successful introduction of Ge atoms into SiO2 substrate was verified quantitatively by Rutherford back-scattering (RBS), which also confirmed that there was no considerable diffusion or loss of Ge atoms due to post-implantation thermal treatment. Ge-QDs are formed when implanted Ge atoms become de-mixed and aggregated into Ge nanoparticles. The formation of the second phase as QDs in SiO2 was determined by low-frequency Raman (LFR) and Transmission Electron Microscopy (TEM). The chemical nature of QDs was identified by the appearance of Ge-related signals in grazing incidence X-Ray Diffraction (XRD) and from characteristic vibrational modes in Raman spectroscopy. Grazing Incidence Small Angle X-ray Scattering (GISAXS) at the Synchrotron Elettra was used to determine the morphology, size, shape, inter-particle distance and spatial correlation of Ge-QDs as well as depth profiling of these properties in implanted layer ; all that as a function of implantation and post-implantation parameters. It was found that Ge-QDs synthesize already during implantation but as amorphous nanoparticles of few nm size. These QDs crystallize after annealing ; the best crystal quality was obtained for Ta = 700-800 oC. Up to Ta = 800 oC, QDs form 3D arrays of particles, which are spherical, distributed isotropically in the subsurface layer of SiO2 and spatially correlated. For higher Ta or too long ta, the crystal quality of QDs reduces and their spatial correlation deteriorates.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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