UCLA Engineering: Scientists Invent Polystyrene-based High-speed Digital Memory Device

UCLA Materials Scientists Invent Polystyrene-based High-speed Digital Memory Device Using Nanotechnology

Date: November 28, 2004
Marlys Amundson
marlysa@support.ucla.edu
(310) 206-0680

Yang Yang
yy@seas.ucla.edu
(310) 825-4052

A team of scientists at the University of California, Los Angeles (UCLA) have successfully invented a non-volatile plastic digital memory device. In a paper appearing Nov. 28 online in the journal Nature Materials, the researchers outline how they successfully designed a new type of polymer, or plastic, memory device.

The new plastic memory device.

The research group, led by materials science professor Yang Yang in the UCLA Henry Samueli School of Engineering and Applied Science, has successfully demonstrated high-performance of plastic memory devices. The device is made from a polystyrene film containing gold nanoparticles, and holds promise for low-cost, high-density memory storage.

Nano-size materials are billionths of a meter in size, much smaller than the width of a human hair.

The new material has a wide range of potential uses, including, digital memory chips for computers, digital cameras and cell phones, to name a few applications.

“There is a lot of talk about nanotechnology, but our device is a nanoparticle-induced phenomenon. It is the nano size of the gold particles allows them to store the charge and function as a memory device,” said Yang. “It’s a revolutionary technology. We’ve combined a traditional material – polystyrene – and a high-tech material to make it happen.”

He added, “Polystyrene is a commonly used plastic material that comes in many shapes and forms, from foam egg cartons to trays or soup bowls to coffee cups and utensils. And our invention turns this commodity plastics into a high-tech invention.”

Yang’s first generation organic memory devices, created in 2000, were fabricated in a vacuum chamber, and his team wanted to develop a memory device that could be processed more easily. Although polystyrene may seem like an unlikely base material for memory devices, it is inexpensive and easy to work with.

In a solution process, the polystyrene base is carried in a liquid and can be applied through spray, paint or print technology. This method is less complicated than vacuum fabrication methods and also less expensive. Using a solution process, the polystyrene-based material also can be constructed in three-dimensional arrays for high-density storage.

Professor Yang Yang

“There is a growing demand for inexpensive memory storage, and flash memory is expensive and slow,” explains Yang. “Plastic memory devices will be both faster and cheaper than current technology.”

In laboratory tests, the polymer memory device has shown it can meet nearly all of the performance requirements. The team is working to extend its lifetime, so that it can write and erase for a million cycles and store the data for at least 10 years.

“We’re exploring related scientific issues through materials engineering and a fundamental understanding of the device’s operating mechanism to push it to the next level of reliability,” explained Yang. “By partnering with industry, we’re also able to work on practical, commercial issues.”

As a scientist at a public university, Yang feels very strongly that he and his colleagues must not only train their students and ensure receive they the best education available, but also strive to remain at the frontiers of scientific research.

“Our students are the human capital for future technology and industry. When we invent and create new technologies, it’s not just in the scientific front, but also in the application sectors, which leads to the creation of new jobs,” noted Yang.

Yang currently has about 20 graduate students in his lab. In addition to memory devices, his team also is working on the next generation of flexible electronic devices based on electronic plastics. Most of them utilize nanotechnology in one way or another, from nanoparticles to interface modification.

“This is one of the ways in which I think nanotechnology leads to a bright future in the scientific exploration,” said Yang. “Researchers must create novel phenomena based on new materials, and by finding new applications.”

This research project is also supported by the Air Force Office of Scientific Research.