In a collaboration between the U.S. Department of Energy’s Ames Laboratory and Northeastern University, scientists have developed a model for predicting the shape of metal nanocrystals or “islands” sandwiched between or below two-dimensional (2D) materials such as graphene. The advance moves 2D quantum materials a step closer to applications in electronics.
Ames Laboratory scientist are experts in 2D materials, and recently discovered a first-of-its-kind copper and graphite combination, produced by depositing copper on ion-bombarded graphite at high temperature and in an ultra-high vacuum environment. This produced a distribution of copper islands, embedded under an ultra-thin “blanket” consisting of a few layers of graphene.
“Because these metal islands can potentially serve as electrical contacts or heat sinks in electronic applications, their shape and how they reach that shape are important pieces of information in controlling the design and synthesis of these materials,” said Pat Thiel, an Ames Laboratory scientist and Distinguished Professor of Chemistry and Materials Science and Engineering at Iowa State University.
Ames Laboratory scientists used scanning tunneling microscopy to painstakingly measure the shapes of more than a hundred nanometer-scale copper islands. This provided the experimental basis for a theoretical model developed jointly by researchers at Northeastern University’s Department of Mechanical and Industrial Engineering and at Ames Laboratory. The model served to explain the data extremely well. The one exception, concerning copper islands less than 10 nm tall, will be the basis for further research.
“We love to see our physics applied, and this was a beautiful way to apply it,” said Scott E. Julien, Ph.D. candidate, at Northeastern. “We were able to model the elastic response of the graphene as it drapes over the copper islands, and use it to predict the shapes of the islands.”
The work showed that the top layer of graphene resists the upward pressure exerted by the growing metal island. In effect, the graphene layer squeezes downward and flattens the copper islands. Accounting for these effects as well as other key energetics leads to the unanticipated prediction of a universal, or size-independent, shape of the islands, at least for sufficiently-large islands of a given metal.
“This principle should work with other metals and other layered materials as well,” said Research Assistant, Ann Lii-Rosales. “Experimentally we want to see if we can use the same recipe to synthesize metals under other types of layered materials with predictable results.”
Image Credit: Ames Laboratory
News This Week
A Brazilian study published in the journal PNAS describes some of the effects infection by SARS-CoV-2 can have on the central nervous system. A preliminary version (not yet peer-reviewed) posted in 2020 was one of the [...]
A new drug designed by scientists at Scripps Research can turn the COVID-19 virus into a harbinger of its own doom. The drug, NMT5, described in Nature Chemical Biology on September 29, 2022, coats SARS-CoV-2 with [...]
Brain stimulation paired with a nose spray comprised of nanoparticles can increase recovery after ischemic stroke in an animal model, according to scientists from Xi’an Jiaotong-Liverpool University and other universities in China. The nasal spray is [...]
Increasing drug resistance could leave us powerless to fight infections we now consider routine, and scientists are urgently searching for answers. It was just a urinary tract infection (UTI). Helen Osment, a fundraiser from Hertfordshire, had [...]
Daegu Gyeongbuk Institute of Science & Technology (DGIST, President Yang Kook) Professor Hongsoo Choi’s team of the Department of Robotics and Mechatronics Engineering collaborated with Professor Sung-Won Kim’s team at Seoul St. Mary’s Hospital, [...]
Tiny nets woven from DNA strands can ensnare the spike protein of the virus that causes COVID-19, lighting up the virus for a fast-yet-sensitive diagnostic test—and also impeding the virus from infecting cells, opening [...]
Roughly two decades ago, a strategy called optogenetics emerged to control brain activity with lasers. It uses viruses to insert genes into cells that make them sensitive to light. Optogenetics has revolutionized neuroscience by giving researchers [...]
Shigella bacteria, which causes Shigellosis, is the primary cause of bacterial diarrhea and diarrheal death among juveniles under five years of age. Because of the antibiotic resistance of Shigella strains, no commercial vaccines are available to date. [...]
Scientists have built microscopic robots equipped with electronic “brains” that are capable of walking autonomously. A team from Cornell University in the US developed the solar-powered bots as part of research into a new generation of [...]
Blood samples from patients with long COVID who are still suffering from fatigue and shortness of breath after a year show signs of autoimmune disease, according to a study published today (Thursday) [...]
High-grade serous ovarian cancer (HGSOC) is among the deadliest human cancers and its prognosis remains extremely poor. An article published in Advanced Science explored the self-therapeutic properties of gold nanoparticles to identify a molecular axis that [...]
Antimicrobial peptides (AMPs) have a broad spectrum of antimicrobial activity and lyse microbial cells by interaction with biomembranes, offering great potential in designing new therapeutics. The antimicrobial resistance (AMR) caused due to overuse of [...]
Tumor cells are notoriously good at evading the human immune system; they put up physical walls, wear disguises and handcuff the immune system with molecular tricks. Now, UC San Francisco researchers have developed a [...]
Hyperspectral microscopy is an advanced visualization technique that combines hyperspectral imaging with state-of-the-art optics and computer software to enable rapid identification of nanomaterials. Since hyperspectral datacubes are large, their acquisition is complicated and time-consuming. [...]
Malignant brain tumors are cancerous growth in the brain with the possibility of spreading to other parts of the central nervous system (CNS). Brain tumors are highly invasive and have devastating consequences, poor prognosis, [...]
An ultrathin invention could make future computing, sensing and encryption technologies remarkably smaller and more powerful by helping scientists control a strange but useful phenomenon of quantum mechanics, according to new research recently published [...]