Team uses carbon nanotubes for polarized-light detection

July 16, 2013, Rice University
Broadband photodetector for polarized light
These schematic diagrams depict the fabrication process for p-n junction photodectors using flattened, highly aligned nanotube carpets. Credit: X. He/Rice University

Using carpets of aligned carbon nanotubes, researchers from Rice University and Sandia National Laboratories have created a solid-state electronic device that is hardwired to detect polarized light across a broad swath of the visible and infrared spectrum.

The research is available online from the American Chemical Society's journal ACS Nano.

"Detecting polarized light is extremely useful," said Rice's Junichiro Kono, professor of electrical and computer engineering and of physics and astronomy. "Many animals and insects can see polarized light and use it for navigation, communication and more. Humans can't see polarized light, so we rely on devices to do that for us."

Most devices can't detect polarized light directly. Instead, engineers place a grate or filter in front of the detector.

"Our photodetector discerns polarized light intrinsically, much like the in the eyes of animals and insects that see polarized light," said François Léonard at Sandia National Laboratories, one of the lead researchers on the study.

Polarized light consists of individual oscillating parallel to one another. The effect is created when light reflects from a , which is why polarized sunglasses reduce the glare from water, glass and other surfaces. Astronomers use polarized light in a number of ways, and there are a number of applications for in communications and the military.

Rice's new photodetector is the latest development from a collaboration between Rice and Sandia under Sandia's National Institute for Nano Engineering program, which is funded by the Department of Energy. In February, Kono, Léonard and colleagues described a new method for making photodetectors from carpets of carbon nanotubes—long, narrow tubes of pure carbon that are about as wide as a strand of DNA.

The nanotube carpets used in the photodetectors are grown in the lab of Rice chemist Robert Hauge, who pioneered a process for growing densely packed nanotubes on flat surfaces. Xiaowei He, a graduate student in Kono's group, found a way to use Teflon film to flatten these tightly packed nanotubes so that they are aligned in the same direction. Each carpet contains dozens of varieties of nanotubes, and about two-thirds of the varieties are semiconductors. Because each of the semiconducting varieties interacts with a specific wavelength of light, Kono's team was able to show in its earlier work that the flattened, aligned carpets of nanotubes could serve as broad-spectrum photodetectors.

In the ACS Nano study, lead author He used chemicals called "dopants" to alter the electrical properties of the nanotube carpets. He created two types of carpet, one with positively charged carriers (p-type) and another with negatively charged carriers (n-type). By overlapping sections of these two, He and colleagues created a device called a p-n junction, which is a fundamental building block of microelectronics.

"Our work provides a new path for the realization of polarization-sensitive that could be enabled on flexible or nonplanar surfaces," He said.

Explore further: Nanotube photodetector built

More information: pubs.acs.org/doi/abs/10.1021/nn402679u

Related Stories

Nanotube photodetector built

February 27, 2013

Researchers at Rice University and Sandia National Laboratories have made a nanotube-based photodetector that gathers light in and beyond visible wavelengths. It promises to make possible a unique set of optoelectronic devices, ...

Nanotube-based terahertz polarizer nears perfection

January 30, 2012

(PhysOrg.com) -- Researchers at Rice University are using carbon nanotubes as the critical component of a robust terahertz polarizer that could accelerate the development of new security and communication devices, sensors ...

Twisted crystals point way toward active optical materials

September 29, 2011

(PhysOrg.com) -- A nanoscale game of "now you see it, now you don't" may contribute to the creation of metamaterials with useful optical properties that can be actively controlled, according to scientists at Rice University.

Recommended for you

Nanoscale Lamb wave-driven motors in nonliquid environments

March 19, 2019

Light driven movement is challenging in nonliquid environments as micro-sized objects can experience strong dry adhesion to contact surfaces and resist movement. In a recent study, Jinsheng Lu and co-workers at the College ...

OSIRIS-REx reveals asteroid Bennu has big surprises

March 19, 2019

A NASA spacecraft that will return a sample of a near-Earth asteroid named Bennu to Earth in 2023 made the first-ever close-up observations of particle plumes erupting from an asteroid's surface. Bennu also revealed itself ...

The powerful meteor that no one saw (except satellites)

March 19, 2019

At precisely 11:48 am on December 18, 2018, a large space rock heading straight for Earth at a speed of 19 miles per second exploded into a vast ball of fire as it entered the atmosphere, 15.9 miles above the Bering Sea.

Revealing the rules behind virus scaffold construction

March 19, 2019

A team of researchers including Northwestern Engineering faculty has expanded the understanding of how virus shells self-assemble, an important step toward developing techniques that use viruses as vehicles to deliver targeted ...

Levitating objects with light

March 19, 2019

Researchers at Caltech have designed a way to levitate and propel objects using only light, by creating specific nanoscale patterning on the objects' surfaces.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

FastEddy
1 / 5 (4) Jul 17, 2013
Better sun-glasses?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.