"I had a strong interest in physics ever since I was a child, hoping to understand how the universe works. After graduating from high school, I did my undergraduate study in the Department of Physics at the University of Science and Technology of China," Xu Zhang recalled.
The tranquil campus provided Xu Zhang with a comprehensive learning environment, allowing him to enjoy studying. Inspired by Professor Zeng Changgan, he became interested in the field of atomically thin two-dimensional (2D) semiconductors and gradually realized related scientific research could expand and disrupt the existing silicon-based semiconductor industry.
Upon graduation, Xu Zhang joined Massachusetts Institute of Technology (MIT) for his PhD study under the supervision of Professor Mildred Dresselhaus and Professor Tomas Palacios. Cultivated by the MIT's highly innovative environment, Xu Zhang set a goal of developing valuable technologies that could benefit society.
Xu Zhang 's research focuses on exploring atomically thin 2D crystal materials, digging into its excellent semiconducting properties, and looking for new opportunities for the chip industry in the Post-Moore era.
He and his team successfully designed and manufactured a high-frequency integrated circuit based on atomically thin 2D crystals, which might be a breakthrough beyond the traditional silicon-based chip designs.
"[2D crystals] as a newly emerging cutting-edge material, still have a lot of gaps in the understanding of their physical properties." Xu Zhang said.
Therefore, he used an electron cyclotron resonance plasma-based approach to develop a non-intrusive surface functionalization method for 2D materials. In such a system, a large amount of charge transfer occurs while the sp2 planar nature of graphene and its ultrahigh mobility can be maintained. For the first time, Zhang unveiled many unique features of 2D materials that are distinct from conventional 3D electronic ones, which shows both practical and scientific significance.
In recent years, Xu Zhang's other achievement is developing a high-frequency flexible rectenna. He first proposed an innovative device configuration based on a 2D semiconducting-metallic-phase heterojunction, which can significantly reduce parasitic capacitance and series resistance. Such configuration sets a new record of the cutoff frequency and allowed the rectenna to cover Wi-Fi, Bluetooth, and most of the mobile communication bands, including 5G.
This breakthrough technology is expected to transform and upgrade the current network infrastructure, such as Wi-Fi, into potential energy hotspots, providing energy solutions for IoT devices. It has huge application potential in wearable devices, flexible electronics, and the IoT industry.
The emphasis on disruptive technology also determines the direction of Xu Zhang's future research. He is currently an Assistant Professor (tenure-track) in the Department of Electrical and Computer Engineering at Carnegie Mellon University. He will focus on combining ultra-low-power smart chips based on 2D materials and high-frequency wireless energy harvesting technologies to develop distributed sensors that may not require batteries at all.
Xu Zhang believes that the semiconductor field is undergoing an important period of change as many ideas are brand new. In the process of upgrading from the mobile Internet to the Internet of Things, the semiconductor industry will play a key role. There are lots of exciting opportunities.