Dr. John Hennessy

Ongoing studies of future astrophysics mission concepts have identified high efficiency detectors and high reflectivity mirror coatings as high priority technologies, particularly those that can enhance system performance at UV wavelengths shorter than those previously explored by missions like the Hubble Space Telescope. At JPL we have pursued the development of new atomic layer deposition (ALD) processes for metal fluoride materials to extend optical coating performance into the far UV wavelength range, and to explore the benefits of the ALD method in comparison to more conventional thin-film methods like evaporation. Using a unique approach involving anhydrous hydrogen fluoride (HF) as a reactant, we have demonstrated fluoride material with excellent UV properties. This talk will discuss the integration of these materials into two technologies at JPL: the development of detector-integrated UV bandpass filters onto silicon imaging sensors to enable solar- or visible-blind operation; and the demonstration of reflective aluminum mirror coatings protected by ALD fluorides. In both cases additional performance enhancement can also be obtained through the use of novel atomic layer etching (ALE) processes to remove residual oxide contamination. Development details and other applications of these ALD and ALE processes will also be discussed.

Biography:

John Hennessy is a technologist at NASA Jet Propulsion Laboratory in the Advanced Detectors, Systems, and Nanoscience Group. His current research interests include the development of atomic layer deposition processes for optical and electrical applications related to UV detector-integrated filters, UV reflective coatings, and semiconductor surface passivation. He received his BE and PhD degrees in electrical engineering from The Cooper Union, and from the Massachusetts Institute of Technology, respectively.