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

Journal Article · Mon Feb 15 00:00:00 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, Vol. 107, Issue 3; Other Information: DOI: 10.1063/1.3276184; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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