Building better conductors: Ph.D. candidate Jiali Yao advances materials research at ASU

Copper is an essential material in power systems and electronic devices because of its high electrical conductivity. However, even one of the world’s most widely used conductors has its limits. 

Jiali Yao, a materials science and engineering Ph.D. candidate in the School for Engineering of Matter, Transport and Energy, is exploring how to push the limits of copper through the addition of graphene, an extremely thin material with exceptional electrical conductivity.

Pushing the limits of copper

Though copper is a widely used metal conductor for electricity, some energy is inevitably lost as electricity travels through copper wires. Over the past century, improvements to copper’s conductivity have been relatively limited. Yao’s research examines whether coating copper with ultrathin layers of graphene can create a more efficient electrical conductor. 

The work connects to Yao’s motivation to go into the field of materials science and engineering: improving technology to use energy more efficiently. 

“I have always wanted to contribute to work that can make the world a better place,” Yao says. “Electricity is one of the most important forms of energy in modern society, and improving how we generate, transport and use energy can have a broad impact.”

Since beginning her doctoral studies at ASU in the fall of 2022, Yao has worked under the guidance of SEMTE professor Wonmo Kang, building a strong foundation in materials science through hands-on research training and coursework.

As Yao’s time at ASU progressed, so did her research. Her work evolved from improving copper-graphene composites to investigating the underlying mechanisms behind those improvements. 

To examine how graphene affects electrical performance, Yao and her collaborators used chemical vapor deposition to grow graphene on copper surfaces, testing factors including graphene quality, thickness and copper matrix geometry. By optimizing these characteristics, Yao and her team were able to achieve an approximately 17% improvement in electrical conductivity as compared to the pure copper matrix group.

Research earns recognition

The work has marked Yao’s growth as a researcher. Her first first-author paper on copper-graphene composite conductors was published in the journal Small and selected for the journal’s back cover. Most recently, another first-author study focusing on the mechanisms behind the ultrahigh electrical conductivity of the composites was published in Small, and selected for the journal’s front cover.

“It gave me confidence that the questions I was asking and the effort I was putting into the research were valuable,” Yao says. “I began to see myself as someone who could contribute real expertise to the field.”

Beyond the laboratory, Yao’s academic and research accomplishments have earned her recognition. She was awarded the A Better Life Scholarship for the 2025-26 and 2026-27 academic school years. 

“Receiving the scholarship was a meaningful recognition of my academic effort, persistence and growth during graduate school,” Yao says. 

In addition to reducing some of the financial burden of graduate school, Yao says the scholarship will give her more freedom to focus on her research, as well as pursue opportunities to present her work at conferences and network with other researchers. 

Yao expanded her experience beyond the university laboratory through an internship with ASM, where she worked as a Process Engineering and Metrology Joint Intern in the company’s atomic layer deposition, or ALD,  area.

During the course of the internship, Yao was able to apply her materials science background to a semiconductor manufacturing environment. She characterized thin films on wafers at the sub-nanometer and atomic scales, and gained hands-on experience with X-ray photoelectron spectroscopy and low-energy ion scattering. She also contributed to ALD thin-film process development, examining the relationships between processing conditions, device performance and material properties. 

“My biggest takeaway was the importance of cross-functional collaboration,” Yao says. “In an industrial semiconductor environment, progress often requires close communication among process engineers, metrology engineers, hardware and other teams.”

The internship helped Yao connect the skills she developed through her studies with a potential future in the semiconductor industry. 

“After graduation, I hope to contribute to this industry, especially in advanced thin-film materials, semiconductor processing, metrology or next-generation device-related materials.” Yao says. 

Looking toward the future

Looking back on her time at ASU, Yao says she has grown into a more confident and independent researcher. She credits much of that growth to the guidance of Wonmo Kang, whose mentorship has played an important role throughout her doctoral studies.

“He has trained me not only in academic research, but also in how to think more independently and confidently as a scientist,” Yao says. 

In the long term, Yao hopes to contribute to innovations in next-generation storage, logic processing or related materials technologies. 

“I want my research and engineering work to support a greener and more energy-efficient future,” Yao says.