Browsing by Author "Stach, E. A."

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In Situ Growth of Si Nanowires Using Transmission Electron Microscopy
(2013-01-01)
Chou, Y. -C.
;
Wen, C. -Y.
;
Reuter, M. C.
;
Su, D.
;
Stach, E. A.
We discuss the use of the alloy catalyst AgAu to grow silicon nanowires and Si/Ge heterojunctions. Nanoscale particles of the catalyst with compositions Ag:Au varying from 2:1 to 1:2 can be fabricated and used to form Si nanowires with high crystal quality, and SiGe interfaces that are close to atomically abrupt. In situ experiments in the TEM are essential for investigating the mechanisms of growth with these alloy catalysts. We describe the relationship between growth kinetics and catalyst state, as well as the environmental stability of the alloy catalysts.
Synthesis of nanostructures in nanowires using sequential catalyst reactions
(2015-08-01)
Panciera, F.
;
Chou, Y. -C.
;
Reuter, M. C.
;
Zakharov, D.
;
Stach, E. A.
Nanowire growth by the vapour-liquid-solid (VLS) process enables a high level of control over nanowire composition, diameter, growth direction, branching and kinking, periodic twinning, and crystal structure. The tremendous impact of VLS-grown nanowires is due to this structural versatility, generating applications ranging from solid-state lighting and single-photon sources to thermoelectric devices. Here, we show that the morphology of these nanostructures can be further tailored by using the liquid droplets that catalyse nanowire growth as a \'mixing bowl\', in which growth materials are sequentially supplied to nucleate new phases. Growing within the liquid, these phases adopt the shape of faceted nanocrystals that are then incorporated into the nanowires by further growth. We demonstrate this concept by epitaxially incorporating metal silicide nanocrystals into Si nanowires with defect-free interfaces, and discuss how this process can be generalized to create complex nanowire-based heterostructures.