Reactive dc magnetron sputtering of (GeO{sub x}-SiO{sub 2}) superlattices for Ge nanocrystal formation

Journal Article · Mon Feb 15 04:00:00 EST 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3276184· OSTI ID:21476131

Zschintzsch, M; Jeutter, N M; Borany, J von; Krause, M; Muecklich, A ^[1]

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1. Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden Rossendorf e.V., P.O. Box 51 01 19, 01314 Dresden (Germany)

The motivation of this work is the tailored growth of Ge nanocrystals for photovoltaic applications. The use of superlattices provides a reliable method to control the Ge nanocrystal size after phase separation. In this paper, we report on the deposition of (GeO{sub x}-SiO{sub 2}) superlattices via reactive dc magnetron sputtering and the self-ordered Ge nanocrystal formation during subsequent annealing. Attention is directed mainly to define proper deposition conditions for tuning the GeO{sub x} composition between elemental Ge (x=0) and GeO{sub 2} (x=2) by the variation in the deposition temperature and the oxygen partial pressure. A convenient process window has been found which allows sequential GeO{sub x}-SiO{sub 2} deposition without changing the oxygen partial pressure during deposition. The phase separation and Ge nanocrystal formation after subsequent annealing were investigated with in situ x-ray scattering, Raman spectroscopy, and electron microscopy. By these methods the existence of 2-5 nm Ge nanocrystals at annealing temperatures of 600-750 deg. C has been confirmed which is within the superlattice stability range. The technique used allows the fabrication of superlattice stacks with very smooth interfaces (roughness<1 nm); thus the Ge nanocrystal layers could be separated by very thin SiO{sub 2} films (d<3 nm) which offers interesting possibilities for charge transport via direct tunneling.

• OSTI ID: 21476131
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 3 Vol. 107; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
ANNEALING
CHALCOGENIDES
CHARGE TRANSPORT
COHERENT SCATTERING
DEPOSITION
DIFFRACTION
ELECTRON MICROSCOPY
FILMS
GERMANIUM COMPOUNDS
GERMANIUM OXIDES
HEAT TREATMENTS
INTERFACES
LASER SPECTROSCOPY
LAYERS
MATERIALS
MICROSCOPY
NANOSTRUCTURES
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRIC EFFECT
PHOTOVOLTAIC EFFECT
RAMAN SPECTRA
RAMAN SPECTROSCOPY
SCATTERING
SEMICONDUCTOR MATERIALS
SILICON COMPOUNDS
SILICON OXIDES
SPECTRA
SPECTROSCOPY
SPUTTERING
SUPERLATTICES
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
TUNNEL EFFECT
X-RAY DIFFRACTION