Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 40: Topical Session: TEM-Symposium - In-Situ I

MM 40.1: Topical Talk

Mittwoch, 13. März 2013, 15:00–15:30, H25

The kinetics of nanowire growth as seen by ultra-high vacuum transmission electron microscopy — •Frances M. Ross — IBM T. J. Watson Research Center, Yorktown Heights, NY, USA

Nanowires formed from semiconducting materials have exciting applications in electronics and optoelectronics, solid state lighting, sensing, and energy storage and conversion. These applications arise from the ability to control crystal structure and composition with great precision, for example to form abrupt heterointerfaces or specific polytypes. Here we show how direct, in situ observations using ultra-high vacuum transmission electron microscopy can help us understand the mechanisms of nanowire growth. Nanowires are formed by flowing precursor gases onto a heated sample containing catalytic particles. For Si and Ge nanowires, this allows us to visualise the ledge-flow growth mechanism directly and explore the relationship between catalyst phase and interface formation. Here, we focus on III-V nanowires, specifically GaP, where in situ measurements show unexpected changes in growth rate from one atomic layer to the next that depend on local defects. We can understand the differences in kinetics by considering the pathways and chemical potentials of the species involved. In situ microscopy therefore provides a unique view into growth and structural control in these complex and versatile nanomaterials.