Moving light across a semiconducting nanowire via surface acoustic waves

March 13, 2014
GaAs NWs with an indium-doped segment at one end were deposited on top of a LiNbO3 surface. LiNbO3 was used as a host material for SAWs because of its high piezoelectricity. A laser source was used to excite electron-hole pairs. These photo-generated electrons and holes are trapped at the spatially separated and piezoelectrically induced energy minima and maxima at the conduction band (CB) and valance band (VB) edges, respectively. These trapped carriers are then transported by the SAW with acoustic velocity to the (In,Ga)As region, where they recombine in quantum-dot-like centers. 

Researchers at the MESA+ Institute for Nanotechnology at the University of Twente in collaboration with the Paul Drude Institute in Berlin have succeeded in moving light from one end of a semiconducting nanowire to the other by means of surface acoustic waves, a kind of nanoscale earthquakes. The results form an important milestone for the development of semiconductor devices which convert optical signals into electrical ones and vice versa, and bear direct relevance for quantum information processing. The findings were published in the journal Nanotechnology this week.

Light is a very suitable medium to transfer information reliably over large distances, for example by glass fibers. On the other hand, information processing is more conveniently done electronically, taking advantage of all miniaturization and integration realized in semiconductors. Optoelectronic devices, which act as optical-to-electrical or electrical-to-optical transducers, are very much sought after as they connect both technologies.

What the researchers in Twente and Berlin have realized is actually an acousto-optoelectronic device, invoking next to optical and electrical signals, also acoustic ones. Laser light is focused on one end of a semiconductor (gallium arsenide) nanowire, where it excites electrons in the conduction band (CB), leaving holes in the valence band (VB). Both electrons and holes are picked up by a surface acoustic wave (SAW) that is produced at large distance from the wire on the same substrate. The SAW transports the electron-hole pairs efficiently along the nanowire. At the end of the nanowire the electrons and holes are forced to recombine, thereby producing light again. As the SAW travels about 100,000 times slower than light, manipulation can be done much more easily.

The technology developed at MESA+ and the PDI allows that this can be all done at very high frequencies (over 1 GHz) and at the nanoscale. This opens up the way for applying this kind of devices for as well.

Explore further: Researchers demonstrate quantum dots that assemble themselves

More information: "High-frequency acoustic charge transport in GaAs nanowires." S. Büyükköse, A. Hernández-Mínguez, B. Vratzov, C. Somaschini, L. Geelhaar, H. Riechert, W. G. van der Wiel and P. V. Santos, Nanotechnology 25, 135204 (2014).

Related Stories

Researchers demonstrate quantum dots that assemble themselves

February 11, 2013

(Phys.org)—Scientists from the U.S. Department of Energy's National Renewable Energy Laboratory and other labs have demonstrated a process whereby quantum dots can self-assemble at optimal locations in nanowires, a breakthrough ...

Team demonstrates quantum dots that assemble themselves

April 16, 2013

(Phys.org) —Scientists from the U.S. Department of Energy's National Renewable Energy Laboratory and other labs have demonstrated a process whereby quantum dots can self-assemble at optimal locations in nanowires, a breakthrough ...

Researchers develop first single-molecule LED

February 3, 2014

The ultimate challenge in the race to miniaturize light emitting diodes (LED) has now been met: a team led by the Institut de Physique et de Chimie des Matériaux de Strasbourg has developed the first ever single-molecule ...

Recommended for you

Graphene is strong, but is it tough?

February 4, 2016

Graphene, a material consisting of a single layer of carbon atoms, has been touted as the strongest material known to exist, 200 times stronger than steel, lighter than paper, and with extraordinary mechanical and electrical ...

A new way to make higher quality bilayer graphene

February 8, 2016

(Phys.org)—A team of researchers with members from institutions in the U.S., Korea and China has developed a new way to make bilayer graphene that is higher in quality than that produced through any other known process. ...

Nanoparticle ink could combat counterfeiting

February 5, 2016

(Phys.org)—Researchers have demonstrated that transparent ink containing gold, silver, and magnetic nanoparticles can be easily screen-printed onto various types of paper, with the nanoparticles being so small that they ...

Tiniest spin devices becoming more stable

February 3, 2016

(Phys.org)—In 2011, the research group of Roland Wiesendanger, Physics Professor at the University of Hamburg in Germany, fabricated a spin-based logic device using the spins of single atoms, a feat that represents the ...

0 comments

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.