Browsing by Subject "Core-shell Nanowires"

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Open Access
Superenhancers: Novel opportunities for nanowire optoelectronics
(Nature Publishing Group, 2014) Khudiyev, T.; Bayındır, Mehmet
Nanowires play a crucial role in the development of new generation optoelectronic devices ranging from photovoltaics to photodetectors, as these designs capitalize on the low material usage, utilize leaky-mode optical resonances and possess high conversion efficiencies associated with nanowire geometry. However, their current schemes lack sufficient absorption capacity demanded for their practical applicability, and more efficient materials cannot find widespread usage in these designs due to their rarity and cost. Here we suggest a novel and versatile nanoconcentrator scheme utilizing unique optical features of non-resonant Mie (NRM) scattering regime associated with low-index structures. The scattering regime is highly compatible with resonant Mie absorption effect taking place in nanowire absorbers. This technique in its optimized forms can provide up to 1500% total absorption enhancement, 400-fold material save and is suitable for large-area applications with significant area preservation compared to thin-film of same materials. Proposed superenhancer concept with its exceptional features such as broadband absorption enhancement, polarization immunity and material-independent manner paves the way for development of efficient nanowire photosensors or solar thermophotovoltaic devices and presents novel design opportunities for self-powered nanosystems.
Open Access
Tailoring self-organized nanostructured morphologies in kilometer-long polymer fiber
(Nature Publishing Group, 2014-05-06) Khudiyev, T.; Tobail, O.; Bayındır, Mehmet
While nanowires and nanospheres have been utilized in the design of a diverse array of nanoscale devices, recent schemes frequently require nanoscale architectures of higher complexity. However, conventional techniques are largely unsatisfactory for the production of more intricate nanoscale shapes and patterns, and even successful fabrication methods are incompatible with large-scale production efforts. Novel top-down, iterative size reduction (ISR)-mediated approaches have recently been shown to be promising for the production of high-throughput cylindrical and spherical nanostructures, though more complex architectures have yet to be created using this process. Here we report the presence of a hitherto-undescribed transitory region between nanowire and nanosphere transformation, where a diverse array of complex quasi one-dimensional nanostructures is produced by Rayleigh-Plateau instability-mediated deformation during the progress of a combined ISR/thermal instability technique. Temperature-based tailoring of architecturally diverse, indefinitely long, globally parallel, complex nanostructure arrays with high uniformity and low size variation facilitates the development of in-fiber or free-standing nanodevices with significant advantages over on-chip devices.