This Small Business Innovation Research Phase I project aims to enable atomic- and nano-scale imaging of materials and devices at temperatures as low as 10 K through the development of a stable liquid helium transmission electron microscope (TEM) specimen holder. Though TEM imaging modalities are amongst the most powerful metrology tools used in materials science, a long-standing lack of stable ultra-low temperature capabilities limits the range of their application to materials and technologies that operate at relatively high temperatures. Stable ultra-low-temperature capabilities are urgently needed for state-of-the-art TEM machines to enable scientific discovery and development across a broad range of emerging, previously inaccessible fields. This project targets and expands the electron microscopy market (expected to exceed $10 billion by 2028) which is rapidly growing in tandem with metrology needs of semiconductor, quantum device, renewable energy, and life-sciences markets. This project includes the development and testing of a novel cryogenic specimen holder with high stability as well as the quantification of high-resolution TEM imaging and stability metrics at liquid helium temperatures. To successfully gather atomic resolution or high-quality spectroscopic data, high thermal and vibrational stability, long hold times, and precise temperature control are necessary. Current low-temperature holders are not only incapable of reaching cold enough temperatures, but they suffer from significant instabilities and thermal losses, heavily affecting image resolution. They rely on small cryogenic dewars which lead to severe temperature fluctuations and vibrations as the unstable cryogen (liquid helium) rapidly evaporates. This project incorporates an innovative design with controlled liquid helium flow cooling, vibration decoupling, and precise temperature regulation over long hold times. The technology will result in the development of a commercial instrument that turns any TEM into an ultra-low-temperature imaging platform capable of characterizing novel materials for next-generation technologies. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
