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and throughput. By working closely with Samsung, we are enabling their latest generation of Galaxy tablets to deliver high-performance connectivity for an enhanced user experience.”


Anadigics’ 2.4 GHz AWL9280 802.11b/g/n and 5 GHz AWL9580 802.11a/n FEICs leverage the Company’s exclusive InGaP-Plus technology and patented design architectures to combine a high performance power amplifier (PA), low-noise amplifier (LNA), and RF switch on a single die.


This level of integration greatly improves manufacturability and reliability, reduces needed PCB area, and simplifies RF front-end design to speed time-to-market. The complete family of FEICs provides outstanding error vector magnitude (EVM) and noise figure performance, which enables high data throughput.


The 2.5 mm x 2.5 mm x 0.4 mm QFN packageintegrates the PA, LNA, Tx/Rx switch to simplify RF design and reduce time-to-market. With high-accuracy, integrated power detector, and RF ports internally matched to 50 Ohms to reduce PCB space requirements, the low EVM to maintain high-modulation accuracy for exceptional data throughput.


Transistors without silicon


The room temperature tunnelling behaviour of boron nitride (BN) nanotubes has been demonstrated with the aid of gold quantum dots


For decades, electronic devices have been getting smaller, and smaller, and smaller. It’s now possible - even routine - to place millions of transistors on a single silicon chip.


But transistors based on semiconductors can only get so small.


“At the rate the current technology is progressing, in 10 or 20 years, they won’t be able to get any smaller,” notes physicist Yoke Khin Yap of Michigan Technological University. “Also, semiconductors have another disadvantage: they waste a lot of energy in the form of heat.”


Electrons flash across a series of gold quantum dots on boron nitride nanotubes. Michigan Tech scientists made the quantum-tunnelling device, which acts like a transistor at room temperature, without using semiconducting materials. (credit: Yoke Khin Yap)


Scientists have experimented with different materials and designs for transistors to address these issues, always using semiconductors like silicon. Back in 2007, Yap wanted to try something different that might open the door to a new age of electronics.


“The idea was to make a transistor using a nanoscale insulator with nanoscale metals on top,” he says. “In principle, you could get a piece of plastic and spread a handful of metal powders on top to make the devices, if you do it right. But we were trying to create it in nanoscale, so we chose a nanoscale insulator, boron nitride nanotubes, (or BNNTs) for the substrate.”


Yap’s team had figured out how to make virtual carpets of BNNTs, which happen to be insulators and thus highly resistant to electrical charge. Using lasers, the team then placed quantum dots (QDs) of gold as small as three nanometres across on the tops of the BNNTs, forming QDs-BNNTs.


BNNTs are the perfect substrates for these quantum dots due to their small, controllable, and uniform diameters, as well as their insulating nature. BNNTs confine the size of the dots that can be deposited.


In collaboration with scientists at Oak Ridge National Laboratory (ORNL), they fired up electrodes on both ends of the QDs-BNNTs at room temperature, and something interesting happened. Electrons jumped very precisely from gold dot to gold dot, a phenomenon known as quantum tunnelling.


“Imagine that the nanotubes are a river, with an electrode on each bank. Now imagine some very tiny stepping stones across the river,” says Yap. “The electrons hopped between the gold stepping stones. The stones are so small, you can only get one electron on the stone


July 2013 www.compoundsemiconductor.net 93


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