Nanotubes Make Logic Circuits that Use Both Light and Current
IEEE Spectrum has the latest information on speeding up communication between computer chips.
Engineers trying to speed up communication between computer chips have been working on using beams of light to replace the copper traces that shuttle data between microprocessors. Now a pair of researchers at Northeastern University in Boston think they can turn up the speed even more by doing some of the computing with light as well.
Physicist Swastik Kar and mechanical engineer Yung Joon Jung lay belts of carbon nanotubes on top of a silicon wafer. The junction created by the intersection of the two materials proved to be highly sensitive to light; shining a laser spot on it caused a sharp rise in the light-induced current. That allowed the pair to build logic circuits that could be manipulated both electrically and optically.
“What we’ve done is built a tiny device where one input can be a voltage and the other input can be light,” Kar says.
The researchers built an optoelectronic AND gate and a two-bit optoelectronic ADDER/OR gate. They also built a four-bit digital-to-analog converter. Shining spots of light onto an array of these junctions converts the digital signal of the laser into an analog current, with the strength of the current depending on the on/off pattern of the laser.
Jung creates the nanotubes in solution, and they can then be placed on a patterned silicon/silicon oxide substrate, so the technology should be compatible with existing CMOS processes, he says. The process should also be reproducible and scalable to large numbers of junctions.
Adafruit has had paid day off for voting for our team for years, if you need help getting that going for your organization, let us know – we can share how and why we did this as well as the good results. Here are some resources for voting by mail, voting in person, and some NY resources for our NY based teams as well. If there are additional resources to add, please let us know – adafruit.com/vote
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.