2 research outputs found
Orthogonal Ambipolar Semiconductor Nanostructures for Complementary Logic Gates
We
report orthogonal ambipolar semiconductors that exhibit hole
and electron transport in perpendicular directions based on aligned
films of nanocrystalline “shish-kebabs” containing polyÂ(3-hexylthiophene)
(P3HT) and <i>N,N′</i>-di-n-octyl-3,4,9,10-perylenetetracarboxylic
diimide (PDI) as p- and n-type components, respectively. Polarized
optical microscopy, scanning electron microscopy, and X-ray diffraction
measurements reveal a high degree of in-plane alignment. Relying on
the orientation of interdigitated electrodes to enable efficient charge
transport from either the respective p- or n-channel materials, we
demonstrate semiconductor films with high anisotropy in the sign of
charge carriers. Films of these aligned crystalline semiconductors
were used to fabricate complementary inverter devices, which exhibited
good switching behavior and a high noise margin of 80% of 1/2 V<sub>dd</sub>. Moreover, complementary “NAND” and “NOR”
logic gates were fabricated and found to exhibit excellent voltage
transfer characteristics and low static power consumption. The ability
to optimize the performance of these devices, simply by adjusting
the solution concentrations of P3HT and PDI, makes this a simple and
versatile method for preparing ambipolar organic semiconductor devices
and high-performance logic gates. Further, we demonstrate that this
method can also be applied to mixtures of PDI with another conjugated
polymer, polyÂ[2,5-bisÂ(3-tetradecylthiophen-2-yl)ÂthienoÂ[3,2-<i>b</i>]Âthiophene]) (PBTTT), with better hole transport characteristics
than P3HT, opening the door to orthogonal ambipolar semiconductors
with higher performance
Combined input and output all-optical variable buffered switch architecture for future optical routers
Abstract—We present a novel optical packet switching fabric ar-chitecture incorporating both input single-stage and output mul-tistage all-optical variable delay buffers as combined input and output queues. For a given optical buffer size (1000 B), the pro-posed architecture, which has combined input and output optical variable buffer queues with optimum partition, achieves packet loss rates (3.4E-5) that are three orders of magnitude lower than the case without the variable buffers and two orders of magnitude lower than the cases with input or output optical queues alone. Index Terms—All-optical packet switching (OPS), all-optical variable buffer, optical router, slow light, switching fabric archi-tecture. I