IBM makes first steps toward carbon nanotube-based nanophotonic devices

Big Blue said its researchers achieved this development by combining a single nanotube-based field-effect-transistor with a pair of metallic nano-mirrors on a chip, and controlling optical emission properties from the nanotube, including emission wavelength and distribution of emitted light.

By Ann Steffora Mutschler, Senior Editor -- Electronic News, 8/25/2008

Building on its continued work in nanotechnology, IBM Corp said today that scientists in its Yorktown Heights, NY-based facility have integrated and controlled an electrically-driven, nanoscale light emitter based on a single carbon nanotube which they said is an important first-step in the development of nanotube-based integrated electronic and nanophotonic devices.

For more on carbon nanotubes from EDN, see: Carbon nanotubes may have a darker side Applied Nanotech, German university apply carbon nanotubes to flexible electronics Nantero, SVTC installing CMOS-friendly carbon nanotube process Carbon nanotubes behave like asbestos, study shows Stanford tries nanotubes for on-chip interconnect Carbon nanotubes boost flexible thin-film transistors IBM moves carbon nanotubes closer to semi use with measurement technique Circuit-design technique could make carbon nanotubes useful

IBM said its scientists furthered the development of carbon nanotube transistor devices by controlling the light emission from a nanotube, and by manipulating and directing light from a single carbon nanotube. As such, the researchers achieved this milestone in the potential development of nanotube-based “nanophotonic” devices, with the goal of building ICs that manipulate light signals, similar to the way electrical signals are manipulated in today’s silicon-based computer chips.

This development involved a series of steps, with the first being IBM scientists combining a single nanotube-based field-effect-transistor (FET) with a pair of metallic nano-mirrors on a chip. The scientists said they were then able to control the optical emission properties from the nanotube which is 2-nm in diameter, including the emission wavelength, the spectral and spatial distribution of the emitted light, and even the efficiency of the emission.

This work demonstrates an unprecedented level of control over electrically-driven light nano-emitters, IBM believes.

IBM said that scientists have known how to control the emission from optically active materials for some time using optical cavities, in which light can bounce back and forth, and interact with the active materials and the cavity leading to emitted light whose characteristics are dominated by the cavity structure, with the laser being one example of a cavity-controlled light source.

By proving that nano-cavities can be used to control and improve the properties of individual, single-walled carbon nanotubes, IBM said its researchers have opened up the possibility of their use in integrated nanophotonic circuits, quantum optics and high performance, on-chip optical interconnects and sensors.

The technology is described in detail in the journal Nature Nanotechnology.



Building an optical cavity around the light-emitting nanotube mirrors (see bottom and top), IBM scientists were able to confine wavelengths to the desired 1.55-micron communications frequency. (Source: IBM)