Chirality Distributions for Semiconducting Single-Walled Carbon Nanotubes Determined by Photoluminescence Spectroscopy

To realize single-walled carbon nanotube (SWCNT) chiral selective growth, elucidating the mechanism of SWCNT chirality (n,m) selectivity is important. For this purpose, an accurate evaluation method for evaluating the chirality distribution of grown SWCNTs without post-growth processing or liquid-dispersion of SWCNTs is indispensable. Here, we used photoluminescence spectroscopy to directly measure the chirality distributions of individual semiconducting SWCNTs suspended on a pillar-patterned substrate. The number of chirality-assigned SWCNTs was up to 332 and 17 chirality types with the chiral angles ranging from 0° to 28.05° were detected. The growth yield of SWCNTs was confirmed to primarily depends on the chiral angle in accordance with the screw dislocation model. Furthermore, when higher-yield chiralities are selected, the chiral angle distribution with a peak corresponding to near-armchair SWCNTs is well fitted with a model that incorporates the thermodynamic effect at the SWCNT-catalyst interface into the kink growth-based kinetic model. Our quantitative and statistical data provide new insights into SWCNT growth mechanism as well as experimental confirmation of theoretical predictions

17.4 Hierarchical Power Distribution and Power Management Scheme for a Single Chip Mobile Processor

A hierarchical power distribution methodology that enables more than dozen power domains in a chip and a power management scheme using 20 power domains are described. This method can achieve very low leakage current in the partial active mode of a single chip mobile processor. The single chip mobile processor embedded three CPU’s that is baseband processor, application processor, and multi-media processor. In the “waiting for calling” mode of the mobile handsets, application processor and multimedia processor part can be power-off. This chip can power off these power domains although the some of baseband parts are actively operating.. Many new techniques for multiple power domains in the chip are described