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Researchers have devised a way to build memory from graphene

Storage in today's computers is based on rotating magnetic platters or flash memory. Both of these mediums work well, provide large amounts of storage and have been around for a while now. Some scientists don’t believe that flash is the future for storage in computers and electronic devices. In fact, the future of storage could be based on something kids use every day at school -- pencil lead or graphite.

A team of researchers at Rice University has found a method of creating a new type of memory from a strip of graphite only 10 atoms thick. Graphite is the basic element in the new type of memory. The scientists describe in a paper published in the online journal Nature Materials a storage device that utilizes the conducting properties of graphene. A large clump of graphene is better known as graphite, something school kids doodle with everyday.

Rice professor James Tour says that graphene memory would increase the amount of storage in a two-dimensional array by about five times. He says that this massive improvement is due to the individual bits being able to be made smaller than 10 nanometers. By comparison, circuitry in your average flash memory chip today is 45nm. Another big benefit of graphene memory is that switches can be controlled by two terminals rather than the three terminals used in flash memory today.

The two-terminal capability is important because it provides the capability to make three-dimensional memory practical since the very thin graphene arrays can be stacked, multiplying the storage capacity of the array with each graphene layer.

Storage arrays using graphene will be mechanical devices at their core and as such, the chips will consume very little power. Much lost power in flash storage comes from leakage; graphene memory will need little power leading to less leakage while keeping data intact. Graphene memory has a massive improvement in on-off power ratio compared to current memory technologies.

Tour said in a statement, "It’s (power savings) huge — a million-to-one. Phase change memory, the other thing the industry is considering, runs at 10-to-1. That means the ‘off’ state holds, say, one-tenth the amount of electrical current than the ‘on’ state."

Tour explains that current tends to leak from an off that is holding a charge. He says, "That means in a 10-by-10 grid, 10 ‘offs’ would leak enough to look like they were ‘on.’ With our method, it would take a million ‘offs’ in a line to look like ‘on'. So this is big. It allows us to make a much larger array.”

Another benefit of graphene as a storage medium is that while it puts off little heat, it is able to operate in a very wide temperature range. The researchers have tested the system to minus 75 to over 200 degrees Celsius.

Performance of graphene-based systems is impressive, the researchers say that the new switches are faster than the lab's testing equipment can measure and they promise long life as well. "We’ve tested it in the lab 20,000 times with no degradation,” said Tour. “Its lifetime is going to be huge, much better than flash memory."

The processes uses graphene deposited on silicon via chemical vapor deposition making for easy construction that can be done in commercial volumes with methods already available says Tour.



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RE: Not quite correct
By randomly on 12/19/2008 2:41:03 PM , Rating: 2
The confusion in the article comes from improper use of the word 'holds' instead of 'conducts' in the following sentence.
quote:
That means the ‘off’ state holds, say, one-tenth the amount of electrical current than the ‘on’ state.


'Holds' is usually used in conjunction with 'charge', not 'current', which creates the confusion. It should have said a PRAM memory cell conducts one-tenth the current in the off state as it does in the on state.

The higher the current ratio difference between the on and off states allows you more freedom in how you organize your memory array. Instead of 10 cells to a bit line you may be able to put thousands on a bit line. This can give you an advantage in over-all power consumption but other factors come into play such as the conductivity of a memory cell, the loading it creates on a bit line, the voltage swings needed for the technology, support circuitry needed, sense amplifiers, the speed requirements of the memory and so on.

A 1,000,000:1 current ratio between on and off states does not mean 100,000 times less power dissipation compared to a 10:1 current ratio. It may give you almost no improvement.

Note also that they are comparing it to PRAM which isn't even commercially available yet.

Graphene memory certainly seems to have a lot of promise, not least of which is that it's almost impervious to radiation, an essential requirement for laptops in a future world full of Nuclear Reactors.


RE: Not quite correct
By masher2 (blog) on 12/19/2008 2:44:51 PM , Rating: 2
quote:
> "'Holds' is usually used in conjunction with 'charge', not 'current', which creates the confusion."
Absolutely right...and the article specifically states "charge" further on, which compounds the confusion.

quote:
it's almost impervious to radiation, an essential requirement for laptops in a future world full of Nuclear Reactors.
Whoa, whoa. If you live in a New England or Rocky Mountain state, your own backyard is far more radioactive than anything outside the containment dome of a nuclear reactor.


RE: Not quite correct
By randomly on 12/19/2008 2:56:51 PM , Rating: 2
ok, ok. I was just joking with the nuclear comment... heh. Couldn't resist pushing that button ;-)

I'd classify myself as pragmatically pro-nuclear with some concerns. Although I'd really like to see somebody throw enough money at polywell fusion to either prove or disprove it's viability. It would be nice to sidestep all the stickier nuclear power issues. Tokamak fusion doesn't look like it will ever be economical.

Other than that I don't see any economically viable long term energy sources other than nuclear unless somebody waves a magic wand and solves the energy storage problem.


RE: Not quite correct
By BZDTemp on 12/20/2008 3:13:28 PM , Rating: 2
The answer is blowing in the wind :-)

Plus of course there is solar power, wave power, tidal power, geothermal power... and finally power generated from biogas (not sure it's the right word but the gas coming from waste treatment plants).

I think the combination of improvement if green energy generation and the expanded use of that tech. Plus the energy savings from improved isolation, transport and manufacturing will get us to a situation where oil is something we use for anything but the normal transportation and heating. That way we can keep using it for lubrication, fertilizer and other stuff which is hard to replace.

Nuclear plants have all sorts of problems. The apparent danger is just the immediate one there is the whole waste problem plus it's not like mining uran, making it usable a fuel or for that matter building and running nuclear power plants are without environmental impact!

The only plus with nuclear power I can think of is that soon Israel will have to stop behaving like a school bully (If one nation should know not to put people in camps it's Israel).


RE: Not quite correct
By masher2 (blog) on 12/21/2008 3:58:23 AM , Rating: 2
As you well know, nuclear waste was a problem solved decades ago. Even though anti-nuclear fanatics have denied us a dedicated storage facility, nuclear reactors continue to do what they've done for the last half-century -- store their waste on site. The actual amount is trivial: a couple cubic meters a year for the average reactor.

An even simpler solution would be to just drop it in the deep ocean. Compared to the trillions of tons of natural uranium, thorium, radium, and radioactive potassium found naturally in the oceans, we could do this for thousands of years without even measurably raising radiation levels.

An utter nonissue.


RE: Not quite correct
By Shmak on 12/21/2008 1:09:41 PM , Rating: 2
BZD, you seem to have missed this:

quote:
Other than that I don't see any economically viable long term energy sources other than nuclear unless somebody waves a magic wand and solves the energy storage problem.


We have plenty of ways to gather renewable energy as you've mentioned but no viable way to store it. This is actually the major problem. Off topic though, sorry.


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