In this talk, I will discuss the recent advances of nanoscale III-nitride semiconductors and their applications in artificial photosynthesis and ferroelectric devices. Artificial photosynthesis, the chemical transformation of sunlight, CO2, and H2O into clean chemicals and fuels, has been extensively studied but faces fundamental challenges of efficiency, stability, and selectivity. Recent studies of III-nitride semiconductors, e.g., GaN, InN, and their alloys, have shown that their surfaces can be transformed to be oxynitride during harsh photocatalysis conditions, leading to significantly improved efficiency and stability. With the integration of various co-catalysts, we have demonstrated high efficiency, long-term stable solar water splitting and hydrogen production. The recent advances of converting CO2 to liquid fuels, reduction of N2 to ammonia, and methane oxidation to methanol will also be discussed. Another recent exciting development is the discovery of ferroelectricity in III-nitride semiconductors. The incorporation of rare-earth elements such as scandium (Sc) can transform conventional III-nitride semiconductors to be ferroelectric. I will present recent advances of ferroelectric nitride heterostructures and nanostructures, including epitaxy, properties, and emerging device applications. Molecular beam epitaxy and properties of ScAlN and ScGaN with a wide range of Sc compositions will be discussed. The realization of ultrathin ferroelectric nitride heterostructures and the underlying physics and interface properties will be discussed, together with their applications in quantum photonics and electronics.
Zetian Mi is a Professor in the Department of Electrical Engineering and Computer Science at the University of Michigan, Ann Arbor. His teaching and research interests are in the areas of low dimensional semiconductors and their applications in electronics, photonics, clean energy, and quantum devices. Prof. Mi has received the Science and Engineering Award from W. M. Keck Foundation in 2020, the IEEE Photonics Society Distinguished Lecturer Award in 2020, the David E. Liddle Research Excellence Award in 2021, the IEEE Nanotechnology Council Distinguished Lecturer Award in 2023, the ISCS Quantum Devices Award in 2024, and the Rexford E. Hall Innovation Excellence Award in 2024. Prof. Mi currently serves as the Editor-in-Chief of Progress in Quantum Electronics and the Serial Editor of Semiconductors and Semimetals. He served as the Vice President for Conferences of IEEE Photonics Society from 2022 to 2023. Prof. Mi co-founded NS Nanotech Inc. and NX Fuels Inc. Prof. Mi is a fellow of IEEE, APS, Optica, and SPIE.