Grant: Research Tools and Instruments

Electrical conductors are generally assumed to also conduct heat well. Defying this conventional wisdom, my research group at the University of British Columbia has discovered the Heat Trap effect: the strong confinement of heat in certain nanostructured conductors and the subsequent thermionic emission of electrons. For the past 6 years, this highly surprising effect has formed the core of my research program along two thrusts: 1) elucidating its physics and 2) establishing it as a foundational technology for multiple promising applications. Heat Trap potentially addresses the fundamental challenge of heat-to-electricity conversion using thermionic and thermoelectric mechanisms: minimizing heat flow while allowing electrons to flow freely. Vast amounts of waste heat exist all around us, in both large-scale power plants and everyday scenarios; sunlight can also be easily converted to heat. Therefore, high-performance thermionic and thermoelectric devices may enable a paradigm shift in large-scale and distributed electricity generation. Other applications include extremely low-cost electron microscopes to bring very-high-resolution imaging to the general public; microstructured vacuum tubes for ultra-high-speed electronics; novel detectors for broadband imaging and radiation sensing; future phononic circuits that exploit waste heat for information processing. This groundbreaking work has earned me an international leadership status in the renascent field of thermionics, leading to over 20 invited talks at prestigious academic and industrial venues as well as collaborations with the Max Planck Institute, Stanford University and the National Research Council, with more being planned. In 2014, I was among ~15 invited participants in NASAs exclusive Thermionics workshop to strategize for the future of the field; in 2016, I was Chair of the 29th International Vacuum Nanoelectronics Conference, the premier international conference of my field. While we have made great strides in understanding the physics of Heat Trap, lack of a crucial category of information continues to hinder our progress: the kinetic energy distribution of the electrons being emitted from the hot spot. This is a central aspect of the systematic investigation of the phenomenon and holds a key to unravelling the mesoscopic effects at play. Equally importantly, the electron energy distribution directly affects the device performance in all of the above applications, and is thus critical for device design and engineering. This proposal is to request funding for a hemispherical electron kinetic energy analyzer, to be integrated into our custom-designed/built ultra-high-vacuum apparatus used for characterizing the Heat Trap effect. The versatility of the apparatus will also allow us to study a wide range of other phenomena related to the optical and thermal excitation of electrons in nanostructures.