11-01 :: December 2010 / January 2011

nanotimes News in Brief

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Fig. 1: Integrated carbon nanotube-based circuit manufacturing on plastic substrates using gas-phase filtration and trans- fer processes. © Aalto University / Professor Esko I. Kauppinen

nic semiconductor TFTs and carbon nanotube TFTs reported so far, as shown in Fig. 2, and equal to the performance of low-temperature polycrystalline sili- con as well as zinc oxide TFTs, which are manufac- tured using high-temperature processes and vacuum- based processes.

The gas-phase filtration and transfer processes can be applied to manufacture devices on any substrate material. This time, the researchers integrated the high-performance carbon nanotube TFTs on plastic substrates, and achieved successful operations of ring oscillators*1

and flip-flops*2 (Fig. 3). High-speed

operations have been achieved with a delay time of 12 microseconds per logic gate. The flip-flops that have been manufactured through these processes are the world’s first carbon nanotube-based synchronous sequential logic circuits*3

.

*1 Ring oscillator: An oscillator circuit composed of inverters connected in a ring. The oscillation frequency is determined by the invertors lag time and number of inverters, and is frequently used to assess the speed of the inverter.