If you drive east from Highway 280 on Page Mill Road in Palo Alto, CA, it’s hard to miss Hewlett-Packard. The giant computer maker’s stately headquarters sprawls along the right side of the street, overlooking a maze of parking lots. Harder to spot is Nanosys, a small nanotechnology startup tucked away in a low-slung bungalow across the road.
But Nanosys’s humble facade masks the bubbling excitement of one of nanotech’s hottest startups. Emerging from conference room Selenium-rooms here are named after elements in semiconductor materials-Stephen Empedocles, Nanosys’s cofounder and director of business development, and Erik Scher, a Nanosys chemist, produce two small vials of what looks like snow cone syrup, one glowing blue and the other red. In the vials are “nanocrystals,” tiny semiconductor particles. Since the crystals are too small to be seen by the naked eye, Scher switches on a computer that displays their magnified images; spheres, stars, and thin rods fill the screen. Nanosys is betting that these particles will be building blocks of the coming commercial revolution in nanotech.
Because the particles are engineered on the nanometer scale, Empedocles says, many of their fundamental properties-chemical, optical, electronic-can be precisely controlled. Nanosys researchers believe that by manipulating the crystals’ composition, size, and shape, they can make a wide range of nano-based devices optimized to conduct electricity, sense chemical reactions, or convert energy from one form to another. Nanosys is beginning to use these resources to design novel products: supercheap solar cells that will show up in construction materials in the next few years; faster, lighter, and more efficient computer displays that could be commercially ready within five years; and nanoscale lasers, sensors, and computer chips that, farther down the road, could have widespread applications in electronics.
That’s the promise, at least. And while dozens of other startups are also vying to emerge as the first successful company to develop nanodevices (see “Other Startups in Nanoelectronics,” below), Nanosys appears to be in a particularly strong position. The company has signed on some of nanotech’s leading academic researchers and has built up a body of scientific expertise reminiscent of powerhouses like Genentech in the early days of the biotech industry. And with more than $70 million in financial assets, including venture capital investments, corporate partnerships, and federal research grants; the rights to some 150 patents; and alliances with large manufacturers like Intel, Nanosys also seems to have the business resources to play a leading role in transforming nanotech into a viable industry.
“What Nanosys is doing is very important,” says R. Stanley Williams, director of quantum science research at HP and an expert on nanoscale electronics. By targeting specific products, like solar cells and computer displays, the startup has focused its know-how on real markets. “They’re taking this core expertise that’s being developed around nanotechnology and finding an economic niche for it by inserting it into something that’s already used or needed today,” says Williams.
For the fledgling nanotech industry, however, the window of opportunity will not stay open indefinitely. After several years of hype over its potential, if nanotech fails to meet expectations to “get the first real products out in the next couple of years,” says Empedocles, “the industry could be in trouble.” And the clock is ticking for Nanosys in particular, since its financial backers are counting on a return on investment in another three to five years. While no one expects Nanosys to compete with the HPs and Intels of the world anytime soon, it does need to hit the market quickly to prove itself-and help dispel the notion that nanotech’s potential is overblown.
Other Startups in Nanoelectronics
|Kovio (Sunnyvale, CA)||Nanoparticle-based printable electronics for chips and displays|
|Nanomix (Emeryville, CA)||Nanotubes for sensors and displays|
|Nantero (Woburn, MA)||Nanotubes for fast, dense, low-power memory chips|
|ZettaCore (Denver, CO)||Molecular electronics for ultradense memory systems|
Nano Solar Cells
The story of Nanosys begins with Larry Bock, a former biotech entrepreneur who is now the company’s executive chairman. In the 1980s and ’90s, Bock helped start 14 biotech companies, including Athena Neurosciences, which was acquired by Elan Pharmaceuticals for $700 million in 1996. But by the late 1990s, Bock had soured on opportunities for startups in biotech. “It used to be you could cut five deals with big pharma and go public,” he says. “Then all of a sudden, there weren’t even five big pharma companies around.” Barely in his 40s, Bock went into retirement.
Browsing through the journal Science one day, Bock was astounded to see so many articles devoted to nanotechnology-“something I had never even heard of,” he says. Intrigued, he spent a year meeting with nanotech experts to identify business opportunities. His conclusion: materials known as inorganic nanocrystals held great potential for near-term products. Unlike more exotic nanomaterials like carbon nanotubes, inorganic nanocrystals were made of silicon and other materials already familiar to electronics makers. Plus, in theory at least, the properties of nanocrystals could be easily manipulated to make useful devices. All of a sudden, Bock was out of retirement and back in the game.
By August 2001, Bock had founded Nanosys together with Empedocles, CEO Calvin Chow, and a handpicked team of top scientists from MIT, Harvard University, and the University of California, Berkeley. The game plan was simple but ambitious: turn this scientific expertise into real products for existing markets-and think big. First on the list: revolutionize energy technology.
One of the recruited scientists was UC Berkeley chemist Paul Alivisatos, who was already using nanotech to try to develop a cheap, renewable energy source. In his basement lab at Berkeley, Alivisatos was building new kinds of materials for solar cells, made of bar-shaped semiconductor rods just two to five nanometers wide and 60 to 100 nanometers long. In 2002, Alivisatos showed that by mixing these “nanorods” with an electrically conducting polymer, he could make a flexible material that behaved much like a traditional solar cell.
Each nanorod absorbs sunlight and turns it into a highly efficient flow of electrons along its length. If the material is sandwiched between two electrodes-say, above and below-then any rods oriented vertically contribute to a usable electric current. And because the nanorods can be grown in one step and processed like plastic-without the high heat, vacuum ovens, or precise layering silicon wafers require-the material is five to ten times cheaper to make than a conventional solar cell.
But it is the overall energy efficiency of the material that really counts. To be a viable product, nano solar cells need to convert 10 to 15 percent of the solar energy they receive into usable electricity. They’re not there yet, but possible solutions are in the works. Alivisatos found, for instance, that if he grew “nanotetrapods” shaped like a child’s jacks instead of rods, the nanomaterial yielded a higher efficiency. It turns out that these new tetrapods are better at herding electrons, so they produce a greater electric current.
In a back room at Nanosys’s Palo Alto labs, Erik Scher is attempting to turn these scientific discoveries into materials suitable for products. To concoct the nano solar cells, he uses a syringe to inject semiconductors into a heated, soapy solution of other chemicals. As the solution cools, the semiconductors crystallize into tiny nanostructures. Empedocles compares the process to making rock candy by supersaturating hot water with sugar-but on the nanoscale. The exact recipe determines the dimensions and solar-conversion properties of the crystals. Then another team of scientists measures how much light each type of crystal absorbs and how much electricity it produces. The result: a sheet of material coated with nanorods and optimized to convert sunlight into electricity.
Recharging Your Roof
Nano solar cells could soon turn sunlight into electrical power for your home. These supercheap solar cells-made of nanocrystal structures in an electrically conducting plastic, sandwiched between flexible electrodes-could be laminated in a thin coating onto ordinary roofing tile. Here’s how it would work (drawing not to scale):
1. Sunlight penetrates the top electrode and is absorbed by the nanostructures (brown).
2. The solar energy excites electrons in the nanostructures, giving rise to an electric current that flows between the electrodes through the nanostructures and the polymer (blue).
3. The electric current is collected by wires and used to charge a battery on the underside of the roof that provides power for appliances, lights, and heating systems.
Unlike conventional solar panels, which can be bulky and unsightly, Nanosys’s finished product could be laminated onto regular roofing tiles or embedded in architectural glass (see “Recharging Your Roof,” above). Wires connected to electrodes that sandwich the material would transmit electric current to a battery or back to the power grid. Spread over large surfaces, these solar cells could provide enough electricity to run home appliances, office equipment, and even buses. Working with Nanosys, Matsushita Electric in Osaka, Japan-a large maker of solar-integrated building materials-plans to put the solar cells into its roofing tiles within a few years.
This could change the future of energy, experts say. Although their market is growing, conventional solar cells have been mainly limited to high-end homes and niche applications like satellites, because they are so pricey to manufacture. For most Americans, solar energy is still five times more expensive than electricity from the power grid. But at one-tenth to one-fifth the cost of conventional solar cells, the Nanosys material could finally make solar power competitive with fossil fuels. “That’s a remarkable claim,” says John Benner, an expert on photovoltaics at the National Renewable Energy Laboratory in Golden, CO. “That changes the face of a lot of things.”
Nanosys is also hoping to spur big changes in another area: consumer electronics. Today’s computer-display manufacturers are limited by two factors. First, manufacturing the high-grade “single crystal” silicon used to make fast chips and processors is expensive and requires high temperatures, and the end product is too brittle to be layered onto large surfaces. Second, while so-called amorphous silicon-typically used in transistors that control whether display pixels are on or off-is easily and cheaply fashioned into thin-film electronics, it has slow electron flow and chews up a lot of power. Nanosys believes it can use nanotech to give the display industry the best of both worlds.
Nanosys is betting that the answer lies in nanowires-inorganic semiconductor structures only a few nanometers in diameter but up to hundreds of micrometers long. Pioneered by Charles Lieber, a chemist at Harvard and a scientific cofounder of Nanosys, nanowires are fast and efficient at moving electrons about. They can be used to create thin-film electronics with the performance of single-crystal silicon. Because their manufacture doesn’t require high temperatures, they can form high-performance electronics on plastic. And they’re cheap to make-like amorphous silicon.
In a first step toward making products for displays, Nanosys is assembling silicon nanowires en masse, using refined versions of techniques developed at Harvard and Berkeley. To grow the nanowires, automated systems control a series of chemical reactions in a vacuum-sealed gas chamber, depositing a “forest” of nanowires onto a glass surface. They harvest the nanowires and lay them down on plastic or glass in a continuous sheet. The aligned nanostructures are then connected to form transistors, using what Empedocles says are the same techniques used to pattern amorphous-silicon transistors.
If it works, this process could transform displays by allowing high-performance electronics to be spread over large areas, such as laptop screens. The result: better pictures and less battery drain. Laptop screens employing such nanowires will be faster and up to three times as energy efficient, says Empedocles. Since they will be made mostly of plastic instead of glass, they will also be lighter and more durable. Nanosys also envisions nanowire-based displays for personal digital assistants and cell phones. Currently, these devices can’t handle video, because the refresh rate of today’s small liquid-crystal displays is too low. With nanowire transistors, however, the screens could refresh much more quickly.
Eventually, nanowires could enable displays with built-in processors and memory, which would replace separate processing modules and hard drives. It’s a technical leap, one that will require making complex circuit patterns and data interfaces out of nanomaterials. But if it becomes feasible-and affordable-it could fundamentally change the devices that you use every day. “You can envision a substantial amount of logic on the display itself,” says David Mitzi, an expert on device electronics at IBM’s Watson Research Center. “You might have an interactive display or even a whole computer on a plastic sheet.”
Vials to Vats
Those are pretty heady ambitions. But for now, Nanosys is looking to be one of nanotech’s survivors. And that means continuing to accumulate scientific expertise, efficiently scaling up its technology for the mass market, and keeping its focus on near-term revenues. While its solar-cell and display-electronics products won’t be ready for a few years, Nanosys has already used its expertise with nanowires to develop a new kind of microarray, or biochip. The company is getting ready to market the chip for DNA and protein analysis in medical applications. The technology will allow researchers to use traditional detection methods, but it will provide up to ten times greater sensitivity than existing devices, in part because its arrays of nanowires have much more surface area for biomolecules to bind to. That could speed up drug discovery and make blood tests more precise-and establish Nanosys as a major player in the billion-dollar market for DNA chips.
The near-term strategy is that sales of these microarrays and other devices nearing completion, as well as revenues from industrial R&D partnerships, will tide Nanosys over as it scales up its production of devices for use in consumer products. The company has already outgrown its original headquarters and is expanding into adjoining buildings in its complex. It is also considering building a large-scale production facility off-site, and its industrial partners have signed on to help sell devices as diverse as solar cells, displays, radio frequency identification tags, light-emitting diodes, and antennas. The plan is that Nanosys will ship out sheets of nano solar cells, thin-film transistors, and other nano-based structures on plastic, and its partners will integrate these materials into products such as roofing tiles, architectural glass, computer displays, and electronic components.
If Nanosys gets that far-and it appears to be well on its way-it will need to grow its crystals in huge vats rather than tiny vials. In turn, transforming these vats of nanocrystals into complex devices like solar cells and thin-film transistors will represent a leap in manufacturing technology. It will also reflect nanotech’s growing up and becoming a commercially viable way to make tomorrow’s electronics. Focusing on how to use nanomaterials in devices such as solar cells may not be “as sexy as building nanocomputers,” Empedocles admits. “But in terms of real market needs and real human needs, I think it’s a huge opportunity.”
So could Nanosys eventually become the next Intel or HP? No one will know for sure until it begins generating black ink on the bottom line-which could be only a couple of years from now. “Until you actually get products out there,” cautions Larry Bock, “you’ll never know whether the timing was right.” One thing is clear: if Nanosys becomes a commercial success, it will be a sure sign that nanotech has come of age.