Tiny silicon nanowire generator harnesses energy from heat produced in electronic circuits

Nov 29, 2011 By Lee Swee Heng
The new thermoelectric generator uses silicon nanowire ‘legs’ to collect heat from hot spots in electronic circuits. Credit: A*STAR Research

Electronic devices often develop ‘hot spots’ that can become detrimental to performance. Much research has focused on developing methods to cool the system, or, even better, convert the excess heat to electricity by exploiting the thermoelectric effect — where a thermal gradient induces the movement of charge carriers. However, previous attempts at building chip-level generators have failed because the incorporated materials were not compatible with the technology used for constructing integrated circuits, such as complementary metal oxide semiconductors (CMOS).

Navab Singh and co-workers at the A*STAR Institute of Microelectronics and the National University of Singapore1 have now created a nanoscale thermoelectric generator (TEG) using silicon nanowire arrays. Silicon, which is compatible with the base materials in CMOS, had previously been discounted due to its poor performance as a generator in bulk form, but it has proved far more effective on the nanoscale.

“Silicon nanowires have much better thermoelectric properties than the parent material, because they have much lower thermal conductivity,” Singh explains. “Also, state-of-the-art equipment is already available for processing silicon. Therefore, if thermoelectric coolers and energy harvesters can be fabricated using silicon nanowires, they can be low-cost, scalable, high-yield devices.”

The researchers constructed their TEG by connecting together two different metal plates using vertical legs made from alternating bunches of n-type silicon nanowires, in which excess electrons carry the charge, and p-type nanowires, in which the charge carriers are ‘holes’ caused by missing electrons (see image). According to Singh, the biggest challenge was connecting the nanowires to the metal plates to allow a low resistivity contact and provide the optimum thermoelectric performance. To do so, they adapted established techniques from CMOS fabrication. “However, high contact resistance on the wire tops remains an issue and our design needs further improvements,” says Singh.

As an electrical generator, a TEG could be used to ‘self-power’ a section of an electronic circuit. “Further, they can be used to generate power and supplement batteries in most high flux systems like automobiles, semiconductor lasers and photo detectors,” suggests Singh. They could also provide an efficient, low-cost cooling system for removing hot spots.

Singh believes nanoscale TEGs could also be used in medical science to power implants in the human body: “A nanowire thermoelectric power generator fits the bill perfectly. They can be scaled to appropriate size and since they lack moving parts, they are reliable and could span the lifetime of the patient. Energy could then be extracted using the temperature gradient between the body and the environment.”

Explore further: A quantum leap in nanoparticle efficiency

More information: Research article in IEEE

Provided by Agency for Science, Technology and Research (A*STAR)

5 /5 (3 votes)
add to favorites email to friend print save as pdf

Related Stories

Solar power, with a side of hot running water

May 03, 2011

MIT researchers and their collaborators have come up with an unusual, highly efficient and possibly less expensive way of turning the sun’s heat into electricity.

MEMS device generates power from body heat

Apr 29, 2010

(PhysOrg.com) -- In an attempt to develop a power source that is compact, environmentally friendly, and has an unlimited lifetime, a team of researchers from Singapore has fabricated an energy harvesting device ...

Recommended for you

A quantum leap in nanoparticle efficiency

15 minutes ago

(Phys.org) —New research has unlocked the secrets of efficiency in nanomaterials, that is, materials with very tiny particles, which will improve the future development of chemical sensors used in chemical ...

A new way to convert light to electrical energy

14 hours ago

The conversion of optical power to an electrical potential is of general interest for energy applications, and is typically accomplished by optical excitation of semiconductor materials. A research team has developed a new ...

Gold nanoparticle chains confine light to the nanoscale

Oct 29, 2014

A multidisciplinary team at the Centre d'Elaboration de Matériaux et d'Etudes Structurales (CEMES, CNRS), working in collaboration with physicists in Singapore and chemists in Bristol (UK), have shown that ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

antialias_physorg
not rated yet Nov 29, 2011
Silicon, which is compatible with the base materials in CMOS

Bit of an understatement. Silicon IS the base material for most all CMOS technology. So of course it is compatible.

the 'slf powerig' stuff is probably not the best application, here (Far better to go to lower power levels in the first place). But the cooling aspect could be exceptionally useful.

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.