News

This month’s issue of IEEE Solid-State Circuits Magazine contains six feature articles on Mark Horowitz.  The articles are a testament to Mark’s decades of contributions, covering his journey from childhood, his contributions to computer architecture and industry, and his guidance of Stanford PhD candidates who continue to become influential researchers.

The six articles by former students, colleagues, collaborators, and Mark himself are titled:

• The Art of Breaking and Making
• Mark Horowitz and his Impact on Computer Architecture
• Rambus
• Mark Horowitz’s Link for Chip-to-Chip Communication
• The Legacy of Mark Horowitz in Me
• Enabling the Hardware for Computational Photography

Congratulations to Mark on this unique honor. The articles are available as PDFs from the IEEE Solid-State Circuits Magazine.

This article is adapted from the IEEE Solid-State Circuits Magazine.

Recently published in Lab on a Chip, a journal of the Royal Society of Chemistry, Professor Audrey Bowden and Gennifer Smith, a PhD student in electrical engineering, detail their new low-cost, portable device that would allow patients to get consistently accurate urine test results at home, easing the workload on primary care physicians.

Other do-it-yourself systems are emerging, but Bowden and Smith's approach is inexpensive and reliable, in part because they base their system on the same tried and trusted dipstick used in medical offices.

Their approach uses an easy-to-assemble black box that allows a smartphone camera to capture video that accurately analyzes color changes in a standard paper dipstick.

Excerpts from Stanford News, May 16, 2016.

Read full Stanford News article

The Alfred P. Sloan Foundation is pleased to announce the selection of 126 outstanding U.S. and Canadian researchers as recipients of the 2016 Sloan Research Fellowships. Awarded annually since 1955, the fellowships honor early-career scientists and scholars whose achievements and potential identify them as rising stars, the next generation of scientific leaders.

"Getting early-career support can be a make-or-break moment for a young scholar," said Paul L. Joskow, President of the Alfred P. Sloan Foundation. "In an increasingly competitive academic environment, it can be difficult to stand out, even when your work is first rate. The Sloan Research Fellowships have become an unmistakable marker of quality among researchers. Fellows represent the best-of-the-best among young scientists."

Awarded in eight scientific and technical fields—chemistry, computer science, economics, mathematics, computational and evolutionary molecular biology, neuroscience, ocean sciences, and physics—the Sloan Research Fellowships are awarded in close coordination with the scientific community. Candidates must be nominated by their fellow scientists and winning fellows are selected by an independent panel of senior scholars on the basis of a candidate's independent research accomplishments, creativity, and potential to become a leader in his or her field.

Congratulations to Jonathan for this outstanding achievement!

The Alfred P. Sloan Foundation is a philanthropic, not-for-profit grant making institution based in New York City. Established in 1934 by Alfred Pritchard Sloan Jr., then-President and Chief Executive Officer of the General Motors Corporation, the Foundation makes grants in support of original research and education in science, technology, engineering, mathematics, and economics. www.sloan.org

Alfred P. Sloan Foundation Press Release

Scientists have been trying for years to make a practical lithium-ion battery anode out of silicon, which could store 10 times more energy per charge than today’s commercial anodes and make high-performance batteries a lot smaller and lighter. But two major problems have stood in the way: Silicon particles swell, crack and shatter during battery charging, and they react with the battery electrolyte to form a coating that saps their performance.

Now, a team from Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory has come up with a possible solution: Wrap each and every silicon anode particle in a custom-fit cage made of graphene, a pure form of carbon that is the thinnest and strongest material known and a great conductor of electricity.

In a report published Jan. 25 in Nature Energy, they describe a simple, three-step method for building microscopic graphene cages of just the right size: roomy enough to let the silicon particle expand as the battery charges, yet tight enough to hold all the pieces together when the particle falls apart, so it can continue to function at high capacity. The strong, flexible cages also block destructive chemical reactions with the electrolyte.

“In testing, the graphene cages actually enhanced the electrical conductivity of the particles and provided high charge capacity, chemical stability and efficiency," said Yi Cui, an associate professor at SLAC and Stanford who led the research. “The method can be applied to other electrode materials, too, making energy-dense, low-cost battery materials a realistic possibility.”

Excerpted from, SLAC Press Release, January 28, 2016.

List of SystemX Alliance affiliated faculty 

Stanford researchers have developed the first lithium-ion battery that shuts down before overheating, then restarts immediately when the temperature cools.

The new technology could prevent the kind of fires that have prompted recalls and bans on a wide range of battery-powered devices, from recliners and computers to navigation systems and hoverboards.

"People have tried different strategies to solve the problem of accidental fires in lithium-ion batteries," said Zhenan Bao, a professor of chemical engineering at Stanford. "We've designed the first battery that can be shut down and revived over repeated heating and cooling cycles without compromising performance."

[...] To address the problem Cui, Bao and postdoctoral scholar Zheng Chen turned to nanotechnology. Bao recently invented a wearable sensor to monitor human body temperature. The sensor is made of a plastic material embedded with tiny particles of nickel with nanoscale spikes protruding from their surface.

For the battery experiment, the researchers coated the spiky nickel particles with graphene, an atom-thick layer of carbon, and embedded the particles in a thin film of elastic polyethylene.

"We attached the polyethylene film to one of the battery electrodes so that an electric current could flow through it," said Chen, lead author of the study. "To conduct electricity, the spiky particles have to physically touch one another. But during thermal expansion, polyethylene stretches. That causes the particles to spread apart, making the film nonconductive so that electricity can no longer flow through the battery."

When the researchers heated the battery above 160 F (70 C), the polyethylene film quickly expanded like a balloon, causing the spiky particles to separate and the battery to shut down. But when the temperature dropped back down to 160 F (70 C), the polyethylene shrunk, the particles came back into contact, and the battery started generating electricity again.

"We can even tune the temperature higher or lower depending on how many particles we put in or what type of polymer materials we choose," said Bao, who is also a professor, by courtesy, of chemistry and of materials science and engineering. "For example, we might want the battery to shut down at 50 C or 100 C."

• Excerpted from Stanford Report, January 11, 2016. Read full article.
• Read NPR's All Tech Considered, January 20, 2016 article

Professor Jelena Vuckovic has been elected as a 2016 Optical Society of America (OSA) Fellow Member. Fellows of the Optical Society are elected based on their significant contributions to the advancement of optics and photonics. Several factors are considered for election, including specific scientific, engineering, and technological contributions, a record of significant publications or patents related to optics, technical or industry leadership in the field as well as service to OSA and the global optics community. 

The OSA Fellow Members Committee reviews nominations submitted by current OSA Fellows and then recommends candidates to the OSA Board of Directors. No more than 10 percent of the total OSA membership may be chosen as Fellows, making the process both highly selective and competitive. As a reflection of the Optical Society's global reach, 60 percent of this year's Fellows reside outside the United States.

Professor Vuckovic's citation reads, "for field opening contributions to the science and engineering of photonic crystals, and in particular, for the use of 2D microcavites for the Purcell-like enhancement of the spontaneous emission rate of embedded quantum dots."

The 2016 class of Fellows will be honored at OSA conferences and meetings throughout 2016. 

Read OSA news release.

Recent articles published by EE Professors Eric Pop and H.S. Philip Wong describe advances in memory and data storage using graphene. The three experiments demonstrate post-silicon materials and technologies that store more data per square inch and use a fraction of the energy of today's memory chips.

The unifying thread in all three experiments is graphene, an extraordinary material isolated a decade ago but which had, until now, relatively few practical applications in electronics.

"Graphene is the star of this research," said Eric Pop, associate professor of electrical engineering and a contributor to two of the three memory projects. "With these new storage technologies, it would be conceivable to design a smartphone that could store 10 times as much data, using less battery power, than the memory we use today."

Professor H.-S. Philip Wong and Pop led an international group of collaborators who describe the graphene-centric memory technologies in separate articles in Nature Communications, Nano Letters, and Applied Physics Letters.

"Data storage has become a significant, large-scale consumer of electricity, and new solid-state memory technologies such as these could also transform cloud computing," Wong said.

Pop and Wong agree that these studies show that graphene is far from a laboratory curiosity. The material's unique electrical, thermal and atomically thin properties can be utilized to create more energy-efficient data storage. Such properties do not exist in the silicon world, yet could potentially transform the way we store and access our digital data in the future.

Excerpts from the Stanford Report. 

Professor Jelena Vuckovic was elected as an American Physical Society (APS) Fellow by the APS Council in October. The election is based on exceptional contributions to the physics enterprise.

Professor Vuckovic's research areas include nanotechnology and NEMS/MEMS, energy harvesting and conversion, photonics, nanoscience and quantum technology, as well as biomedical devices and systems. She leads the Nanoscale and Quantum Physics Lab, and is a faculty member of the Ginzton Lab, Bio-X, and the Pulse Institute.

Her citation reads, "For major and field opening contributions to nano photonics and its application to information science; including the design and fabrication of 2D photonic crystals with integrated quantum dot structures."

Professor Lambertus Hesselink and Assistant Professor Juan Rivas-Davila are two of eight Stanford faculty seed grant recipients. The awards are to assist in new research that promises clean technology and energy efficiency.

Assistant Professor Juan Rivas' and his research team will continue exploration of more energy-efficient power supplies. An initial goal is to provide energy-efficient methods to pasteurize liquids like milk and fruit juice. The team's long-range goal is to revolutionize the design and manufacture of power electronics components. The Precourt Institute for Energy awarded Rivas-Davila's grant.

Professor Lambertus Hesselink's research will assess and design a method to capture heat waste from computers. His team projects that at least 20% of the waste could be recouped, saving $6 million in electricity per day in the U.S. alone. The Precourt Energy Efficiency Center (PEEC) provided this award.

Read the full Stanford report article.

Published in a recent article in Scientific Reports, Professor Vuckovic and her team present the inverse design technique. As stated in the introduction, the "inverse design concept is simple and extendable to a broad class of highly compact devices including frequency filters, mode converters, and spatial mode multiplexers."

"Light can carry more data than a wire, and it takes less energy to transmit photons than electrons," said electrical engineering Professor Jelena Vuckovic, who led the research.

In previous work her team developed an algorithm that did two things: It automated the process of designing optical structures and it enabled them to create previously unimaginable, nanoscale structures to control light. Now, she and lead author Alexander Piggott, a doctoral candidate in electrical engineering, have employed that algorithm to design, build and test a link compatible with current fiber optic networks.

Read the article in Scientific Reports

Read the Stanford Report article