ECE/KIC Colloquium: Hiroshi Amano, 2014 Nobel Laureate

Title: How a poor university lab sparked the blue LED revolution and will have a lasting impact on the net-zero-carbon emission and smart society of the future

Abstract: I would like to focus on the necessity of the research and development of wide bandgap and ultrawide-bandgap semiconductors, particularly GaN, AlN and their alloys, which I believe should play a major role in establishing a net-zero-carbon emission and smart society in the future. The contributions of GaN and related materials to LED lighting for energy savings are huge. The applications of these materials systems are not limited to lighting. By replacing Si-based power devices with GaN-based power devices, we can expect 25% reduction in total electricity consumption. GaN-based high-voltage power devices should become the key devices in establishing renewable-energy-based electricity grids because of their high-speed switching and high-voltage capability. GaN-based high-frequency and high-power transistors will provide a unique solution for realizing millimeter-wave and even THz wireless communication systems. By spatially modifying the alloy composition while maintaining coherent growth, we can realize either a p-type or n-type layer without any impurity doping. These new types of doping, called distributed polarization doping (DPD), has been developed by Professors Debdeep Jena and Huili Grace Xing and applied to p-type AlGaN with high Al composition, for which it had long been very difficult to realize a highly conductive p-layer by Mg doping. In the case of a conventional Mg doping method, the emission wavelength of III-nitride LDs is limited to 338 nm, while with the DPD method, LDs with emission wavelengths as short as 272 nm have been realized. Recently, the room-temperature continuous-wave operation of DUV LDs has been achieved. Using the DPD method, it is also possible to realize a high Al content AlGaN p-n diode without any impurity-doped layer. Research on GaN-based nitrides began at Nagoya University in 1982. At that time, the laboratory was very poor and could not afford an MOVPE reactor. The strong commitment of late professor Isamu Akasaki led to the first demonstration of GaN-based pn-junction LEDs. In this presentation, I would like to describe how GaN-based blue LEDs were born from a poor Japanese university.

There will be a lunch reception before the talk at 12pm in 116 Upson Hall.

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