Synthesis, Modification and Applications of Ge Nanoclusters Embedded in SiO2 Films


Synthesis, Modification and Applications of Ge Nanoclusters Embedded in SiO2 Films

von Borany, J.; Beyer, V.; Heinig, K.-H.; Mücklich, A.; Schmidt, B.; Skorupa, W.

Due to their quantum confinement properties and the large surface-to-volume-ratio, semiconductor and metal nanoparticles embedded in a matrix play a significant role for new functional materials. Among them, Si, Ge, or SiC nanoclusters (-or crystals) are of particular interest for future (opto)electronic devices due to the full compatibility with semiconductor technology.
The contribution focus on recent studies on Ge nanoparticles embedded in dielectric films (mainly SiO2). Based on phase separation of supersaturated solid solutions, Ge nanocluster have been fabricated using ion beam synthesis or magnetron sputtering techniques. The size, density, density and position of the Ge nanocrystals can be varied in a technological relevant way by the degree of supersaturation and the spatial distribution of the Ge. Moreover, subsequent thermal or ion-beam processing enables to tailor nanocluster properties like shape, size or composition. Taking into account the ion beam interaction at interfaces, the generation of delta-like nanocluster bands has been successfully demonstrated. For Ge nanocrystals formation, relatively low process temperatures (< 950°C) are characteristic, but careful processing remains necessary to avoid Ge loss in thin films due to the formation of volatile GeO components. Some conceivable (opto)electronic applications of Ge nanoclusters will be discussed more in detail. Thin gate oxides containing ion beam synthesized Ge nanoclusters have been applied to study “non-volatile” me¬mory with low-field programming (< 5 MV/cm) capability. The violet luminescence in Ge doped SiO2 films was investigated with respect to their possible use to fabricate luminescence or opto-coupling devices. Finally, nanocluster films offer a new interesting approach for light absorption in bandgap engineered absorber materials designed for next generation solar cells.

Keywords: Ion beam synthesis; Ge nanoclusters; Nanocrystal memory; Bandgap engineering; Photovoltaics

  • Invited lecture (Conferences)
    The IUMRS International Conference in Asia 2008 (IUMRS-ICA2008), Session M "Innovative Material Technologies Utilizing Ion Beams", 08.-13.12.2008, Nagoya, Japan

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Publ.-Id: 12313