Professor Hiroshi Amano received Doctor of Engineering from Nagoya University. Currently he is a Director, Center for Integrated Research of Future Electronics, and a Professor, Institute of Materials and Systems for Sustainability, Nagoya University.
He shared the 2014 Nobel Prize in Physics with Prof. Isamu Akasaki and Prof. Shuji Nakamura "for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources". He is currently developing technologies for the fabrication of high-efficiency power semiconductor development and new energy-saving devices at Nagoya University.

Nicolas Grandjean received his PhD in physics from the University of Nice–Sophia Antipolis in 1994 and subsequently joined the French National Centre for Scientific Research (CNRS) as a staff scientist. In 2004, he was appointed tenure-track assistant professor at the École polytechnique fédérale de Lausanne (EPFL), where he founded the Laboratory for Advanced Semiconductors for Photonics and Electronics. He was promoted to full professor in 2009. From 2012 to 2016, he served as Director of the Institute of Condensed Matter Physics at EPFL and was a visiting professor at the University of California, Santa Barbara, in 2016. Between 2018 and 2022, he headed the EPFL School of Physics. In 2025, he was appointed Associate Vice-President for Education. Professor Grandjean has received numerous distinctions, including the Sandoz Family Foundation Grant for Academic Promotion, the Nakamura Lecturer Award (2010), the Quantum Devices Award at the 2017 Compound Semiconductor Week, and the EPFL Best Teacher Award in 2022. He has authored more than 600 peer-reviewed publications and has delivered plenary talks at major international conferences. His research focuses on the physics and technology of III-V nitride wide-bandgap semiconductors.

Blue light-emitting diodes (LEDs) based on III-V nitride semiconductors have enabled the creation of semiconductor light sources with a luminous efficiency ten times greater than that of incandescent light bulbs [1]. Nowadays, these LEDs are ubiquitous in lighting applications. They have sparked a technological revolution that has significantly reduced global electricity consumption.
A remarkable feature of blue LEDs is their exceptionally high internal quantum efficiency, close to 100% at room temperature, despite an enormous dislocation density, on the order of 108 cm-2, inherited from the epitaxial growth of GaN on foreign substrates such as sapphire [2]. To understand this apparent paradox, we need to look at the properties of InGaN/GaN quantum wells (QWs), which form the core of these devices. It was first explained that carriers are localized in random alloy potential fluctuation minima and thereby cannot diffuse toward dislocations [3]. Then it was proposed that the formation of V-shaped pits around the dislocations creates an energy barrier for carriers that hinders their recombination onto the dislocations [4]. In addition to extended defects, impurities and/or native point defects could potentially be non-radiative recombination centers (NRCs) and impair the efficiency of III-nitride LEDs [5,6].
In this presentation, we will begin by discussing the actual epitaxial structure of state-of-the-art blue LEDs. It is interesting to note that they all feature an InGaN layer (or an InGaN/GaN superlattice) beneath the active QW region. We will show that this InGaN underlayer is a prerequisite for obtaining InGaN/GaN QWs with high quantum efficiency. Its role is to trap surface defects generated during the high-temperature growth of GaN by metal-organic vapor phase epitaxy [7,8]. We will demonstrate that these surface defects depend on the growth temperature and react with indium atoms to create NRCs when incorporated into InGaN/GaN QWs. The nature of these defects will be revealed by growth experiments. We will then propose a growth mechanism that explains the surface segregation of these surface defects and their incorporation as an NRC center in the InGaN layers. Finally, we will show that high-efficiency blue LEDs require careful growth optimization: i) screening of threading dislocations by forming topological defects (V-shaped pits) and ii) trapping of surface defects generated during high-temperature growth of the GaN buffer. The prospects for extreme wavelength III-nitride-based LEDs, i.e., the UV-C and red wavelength ranges, will also be discussed.

Joan Redwing is a Distinguished Professor of Materials Science and Engineering and Electrical Engineering at Penn State University. She currently serves as Director of the 2D Crystal Consortium (2DCC), an NSF Materials Innovation Platform national user facility in the U.S. that is focused on advancing the synthesis and characterization of 2D materials for next generation devices. Her research focuses on crystal growth and epitaxy of electronic materials, with an emphasis on thin film and nanomaterial synthesis by metalorganic chemical vapor deposition. She is a fellow of the Materials Research Society, the American Physical Society, and the American Association for the Advancement of Science. She is an author on over 350 publications in refereed journals and holds 8 U.S. patents.

Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs), exemplified by materials like MoS2 and WSe2, have garnered increasing interest for next generation electronics such as gate-all-around nanosheet transistors, neuromorphic devices and sensors/imagers heterogeneously integrated with silicon CMOS technology. The interest in semiconducting TMDs arises from their atomically thin nature and passivated van der Waals surfaces, however, realization of high-performance devices requires advances in TMD synthesis to provide wafer-scale films that can be readily integrated into devices via either direct growth or layer transfer methods.

Our work has focused on the development of metalorganic chemical vapor deposition (MOCVD) as a manufacturing-compatible approach for wafer-scale semiconducting TMDs. The TMDs are grown epitaxially on 2” diameter c-plane sapphire by MOCVD at elevated temperatures (>800 °C) to obtain high crystal quality. Nucleation of TMDs on sapphire is intimately tied to the surface structure and the growth chemistry which can be controlled to achieve unidirectional TMD domains with a significant reduction in mirror twin domains in coalesced films. In situ spectroscopic ellipsometry is demonstrated to be an effective real time monitor of TMD growth even at the sub-monolayer level which can be exploited to track surface coverage as a function of time under varying growth conditions. The ability to precisely control and modulate precursor flux during growth is used to synthesize in-plane heterostructures that enable localized exciton confinement and emission. Applications for wafer-scale TMD monolayers in nanoelectronics, sensing and photonics will be discussed.