In Extraordinary Optical Transmission (EOT), a metallic film perforated with an array of [periodic] apertures exhibits transmission over 100% normalized to the total aperture area, at selected frequencies. EOT devices have potential applications as optical filters and as couplers in hybrid electro-optic contacts/devices. Traditional passive extraordinary optical transmission structures, typically demonstrate un-normalized transmission well below 50%, and are typically outperformed by simpler thin-film techniques. To overcome these limitations, we demonstrate a new breed of extraordinary optical transmission devices, by “burying” an extraordinary optical transmission grating in a dielectric matrix via a metal-assisted-chemical etching process. The resulting structure is an extraordinary optical transmission grating on top of a dielectric substrate with dielectric nano-pillars extruded through the grating apertures. These structures not only show significantly enhanced peak transmission when normalized to the open area of the metal film, but more importantly, peak transmission greater than that observed from the bare semiconductor surface. The structures were modeled using three-dimensional rigorous coupled wave analysis and characterized experimentally by Fourier transform infrared reflection and transmission spectroscopy, and the good agreement between the two has been demonstrated. The drastic enhancement of light transmission in our structures originates from structuring of high-index dielectric substrate, with pillars effectively guiding light through metal apertures.
We report an all-printed flexible carbon nanotube (CNT) thin-film transistor (TFT). All the CNT TFT components,
including the source and drain electrodes, the TFT transport channel, and the gate electrode, are printed on a flexible
substrate at room temperature. A high ON/OFF ratio of over 103 was achieved. The all printed CNT-TFT also exhibits
bias-invariant transconductance over a certain gate bias range. This all-printed process avoids the conventional
procedures in lithography, vacuum, and metallization, and offers a promising technology for low-cost, high-throughput
fabrication of large-area flexible electronics on a variety of substrates, including glass, Si, indium tin oxide and plastics.
We report a voltage-tunable multispectral quantum dot infrared photodetector with
integrated carbon-nanotube based flexible electronics. Such integrated photodetection
and flexible electronics would not only enhance the detectors functionalities, but also
reduce the time delay by performing image processing locally, making it promising for
adaptive multi-spectral photodetection and sensing.