Making a new generation of memristors for digital memory and computation

February 3, 2016 by Allison Mills
Making a new generation of memristors for digital memory and computation
Electronics have come a long way from the 200 megabytes stored on this 75-pound Memorex 667 disk drive. Memristors like the one developed by Yun Hang Hu could push computing into a new era.

Memristors are a new class of electrical circuits—and they could end the silicon era and change electronics forever. Since HP first developed a working prototype with a titanium dioxide film in 2008, engineers have sought to perfect the model.

Now, researchers at Michigan Technological University have made an ideal memristor based on molybdenum disulfide nanosheets. Yun Hang Hu, the Charles and Carroll McArthur Professor of Materials Science and Engineering, led the research, which was published in Nano Letters this January.

Beyond Binary Code

Transistors based on silicon, which is the main component of computer chips, work using a flow of electrons. If the flow of electrons is interrupted in a transistor, all information is lost. However, memristors are electrical devices with memory; their resistance is dependent on the dynamic evolution of internal state variables. In other words, memristors can remember the amount of charge that was flowing through the material and retain the data even when the power is turned off.

"Memristors can be used to create super-fast memory chips with more data at less energy consumption" Hu says.

Additionally, a transistor is confined by binary codes—all the ones and zeros that run the internet, Candy Crush games, Fitbits and home computers. In contrast, memristors function in a similar way to a human brain using multiple levels, actually every number between zero and one. Memristors will lead to a revolution for computers and provide a chance to create human-like artificial intelligence.

Making a new generation of memristors for digital memory and computation

"Different from an electrical resistor that has a fixed resistance, a memristor possesses a voltage-dependent resistance." Hu explains, adding that a material's electric properties are key. "A memristor material must have a resistance that can reversibly change with voltage."

His research revealed that molybdenum disulfide nanosheets are promising for memristors. The material's success comes down to engineering atomic structures.

An ideal memristor is symmetrical. The relationship between current and voltage is even, rounded and equal in both quadrants. In reality, memristors usually show lopsided current-voltage characteristics. However, Hu's molybdenum disulfide memristor does show the ideal symmetry. This will make the material more predictable and consistent as it is developed for use in electronics.

Making a new generation of memristors for digital memory and computation

To get this symmetry, Hu and his research team started with bulk molybdenum disulfide, also known as the mineral molybdenite that used as an industrial lubricant. They then manipulated the atomic, structural arrangements, referred to as different crystal phases. The bulk material with a 2H phase works well as a regular resistor, and to make it a memristor, the team peeled back the molecular layers. This exfoliation process creates molybdenum disulfide nanosheets with 1T phase. The nanosheets with1T phase exhibit a reversible change in resistance relative to voltage—necessary for a memristor. The researchers finally dispersed nanosheets on the two sides of a silver foil to form a symmetric memristor.

"This material is in the very beginning stages for this application," Hu says, adding that new materials and better memristors could radically change the way computers are built. It will start with smaller and faster computer chips, but then he gestures around his office. "These memristor materials will be very versatile, and someday, this white board and that coffee cup could be computers."

And having a symmetrical memristor material brings us closer to that day.

Explore further: A new electronic component to replace flash storage

More information: Peifu Cheng et al. Memristive Behavior and Ideal Memristor of 1T Phase MoS Nanosheets , Nano Letters (2016). DOI: 10.1021/acs.nanolett.5b04260

Related Stories

A new electronic component to replace flash storage

October 19, 2015

Researchers funded by the Swiss National Science Foundation have created a new electronic component that could replace flash storage. This memristor could also be used one day in new types of computers.

HP Labs find memristors can compute (w/ Video)

April 9, 2010

( -- Researchers at HP Labs, the central research arm of HP, have discovered that a resistor with memory, a “memristor” can also perform logic operations. This means chips storing data may also be able to ...

Computers that mimic the function of the brain

April 6, 2015

Researchers are always searching for improved technologies, but the most efficient computer possible already exists. It can learn and adapt without needing to be programmed or updated. It has nearly limitless memory, is difficult ...

Blood simple circuitry for cyborgs

March 30, 2011

Could electronic components made from human blood be the key to creating cyborg interfaces? Circuitry that links human tissues and nerve cells directly to an electronic device, such as a robotic limb or artificial eye might ...

Scientists build a neural network using plastic memristors

January 29, 2016

A collaborative of Russian and Italian scientists has created a neural network based on polymeric memristors, devices that can potentially be used to build fundamentally new computers. According to the researchers, these ...

Recommended for you

Testing TVs and tablets for 'green' screens

August 21, 2017

To improve viewing pleasure, companies have developed television—and tablet screens—that include quantum dots to enhance brightness and color. Some quantum dots are made with potentially harmful metals, which could leach ...

Going nano in the fight against cancer

August 17, 2017

Imagine being able to see the signs of cancer decades before we can now. URI Chemical Engineering Assistant Professor Daniel Roxbury and researchers from Memorial Sloan Kettering Cancer Center have invented a technique that ...


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Feb 03, 2016
"Different from an electrical resistor that has a fixed resistance, a memristor possesses a voltage-dependent resistance."

Surely this is an error. Memristors are supposed to be current dependent resistors.

Many devices have voltage dependent resistance, such as diodes.
5 / 5 (2) Feb 03, 2016
"If the flow of electrons is interrupted in a transistor, all information is lost."
Not in floating gate transistors on which flash memory is based.

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.