Now that plasma televisions are here, their makers would have you believe the quest for the ultimate TV is over. After all, these big, flat screens are dazzlingly bright and have a wide viewing angle. They can be hung on a wall or even built right into it. What more could you want?

Well, for starters, how about a TV set that doesn't consume as much power as a toaster oven? For that matter, you would think that any TV technology worthy of the term ”ultimate” would be free of significant flaws, which lower-end plasma screens are not. For example, many models costing less than about US $5000 have a distracting tendency to render pure black with a greenish cast.

For reasons like those, bands of researchers in the United States, Europe, and Asia are insisting that the last word in TVs won't be plasma, but rather nanotubes. The author holds a waferThese exotic molecules of carbon, only a few nanometers wide and perhaps a micrometer long, are at the heart

of a new class of big, bright experimental displays that could overcome the power and image quality problems of plasma screens while retaining their brightness and size.

At stake is the richest consumer electronics category in the world: in the United States alone this year, people will buy at least 30 million analog and digital television sets worth more than $12 billion, according to the Consumer Electronics Association (CEA) in Arlington, Va. Digital and flat models--precisely the category targeted by the emerging nanotube technology--are the fastest-growing category, the CEA says.

It will be the first consumer application in microelectronics for these sheets of carbon atoms seamlessly wrapped into infinitesimal cylinders. They have been proposed as the basis for a whole host of technologies, including hydrogen storage, interconnects for chips with ultradense components, and a new breed of transistor.

They're also breathing new life into an old idea--displays based on the phenomenon of field emission. Unlike the liquid-crystal displays common in laptops and small video devices, field-emission displays can offer wide viewing angles, and they are inherently less power-hungry than plasma displays, making them cheaper to operate.

With advantages like those, it's no wonder that companies such as Motorola Inc. (Schaumburg, Ill.) and Samsung Group (Seoul, South Korea) are aggressively pursuing field-emission display technology using nanotubes. Samsung, for example, has already demonstrated a full-color 38-inch field-emission display capable of handling normal video frame rates. What's more, a Japanese government-funded consortium was announced earlier this year to develop similar displays, and Sony Corp. (Tokyo) is developing its own nanotube display technology as well.

Plasma demands considerably more electricity than regular television cathode ray tubes (CRTs). A 38-inch color CRT consumes approximately 70 W. A similarly sized plasma display consumes some 700 W--a level of power consumption normally seen only in home appliances, like vacuum cleaners, that are typically in use for only a few minutes a day. Apart from the impact on consumers' wallets, if plasma technology became commonplace, it would result in significant implications for electricity generation and distribution, given that most people watch television for several hours a day and homes (at least in the West) often have multiple televisions. However, a 38-inch field-emission display should be able to provide the same performance as a plasma display while consuming only 50 to 70 W.

Field-emission displays use much less power than plasma displays because they're intrinsically more efficient. Generating visible light from the surface of a plasma display is a three-step process that requires a gas to be ionized, which in turn emits ultraviolet light that stimulates a phosphor to produce visible light. Field emission allows TV makers to do away with the energy-hungry ionization step and stimulate the phosphors directly with electrons.