Dr. Jeffrey M. Woodward Profile

Dr. Jeffrey M. Woodward

at US Naval Research Lab

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Author

Publications (4)

Proceedings Article | 24 August 2021 Presentation + Paper

Advanced AlF3-passivated Aluminum mirrors for UV astronomy

L. Rodríguez-de Marcos, D. Boris, J. Del Hoyo, Virginia Wheeler, Jeffrey Woodward, J. G. Richardson, S. G. Walton, E. J. Wollack, M. A. Quijada

Proceedings Volume 11820, 1182005 (2021) https://doi.org/10.1117/12.2594741

KEYWORDS: Aluminum, Mirrors, Reflectivity, Coating, Plasma, Ultraviolet astronomy

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Efficient ultraviolet (UV) mirrors are essential components in space observatories for UV astronomy. Aluminum mirrors with fluoride-based protective layers are commonly the baseline UV coating technology; these mirrors have been proven to be stable, reliable, and with long flight heritage. However, despite their acceptable optical performance, the single-bounce reflectance values are still too low for use in optical systems in which several reflections are required. Recently, a novel passivation procedure based on the self-fluorination of bare Al has been presented [1, 2]. This research is framed in a collaboration between the Goddard Space Flight Center (GSFC) and the Naval Research Laboratory (NRL), and the experiments are carried out in the Large Area Plasma Processing System (LAPPS) at NRL using bare aluminum samples coated at GSFC coating facilities. The passivation of the oxidized Al is accomplished by using an electron-beam generated plasma produced in a fluorine-containing background to simultaneously remove the native oxide layer while promoting the formation of an AlF₃passivation layer with tunable thickness. Importantly, this new treatment uses benign precursors (SF₆) and does not require high substrate temperatures. This novel procedure has demonstrated improved Al mirrors with enhanced FUV reflectivity. Examples of mirrors tuned at several key FUV wavelengths are provided. The LAPPS has been recently upgraded to include a new spectroscopic ellipsometer for real-time, in situ measurements of film thickness and optical constants of the fluoride layer during the plasma treatment. Since this new capability requires precise knowledge of the complex refractive index (n,k) of AlF₃, we present optical constants in the 90-2500 nm range obtained from Al mirrors previously prepared using the LAPPS process. The derived optical properties from the AlF₃ passivation layer show similar optical properties in the FUV when compared with PVD- and ALD- hot-deposited AlF₃.

Proceedings Article | 12 April 2021 Presentation

Characterization of β-Ga2O3 homoepitaxial films and MOSFETs grown by MOCVD at high growth rates

Marko Tadjer, Fikadu Alema, Andrei Osinsky, Michael Mastro, Neeraj Nepal, Jeffrey Woodward, Rachael Myers-Ward, Evan Glaser, Jaime Freitas, Alan Jacobs, James Gallagher, Alyssa Mock, Daniel Pennachio, Jenifer Hajzus, Mona Ebrish, Travis Anderson, Karl Hobart, Jennifer Hite, Charles Eddy

Proceedings Volume 11742, 117420W (2021) https://doi.org/10.1117/12.2588499

KEYWORDS: Metalorganic chemical vapor deposition, Field effect transistors, Transistors, Silicon carbide, Scattering, Temperature metrology, Silicon, Semiconductors, Roads, Resistance

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Proceedings Article | 5 March 2021 Presentation

High growth-rate MOCVD homoepitaxial [beta]-Ga2O3 films and MOSFETs for power electronics applications

Proceedings Volume 11687, 116870S (2021) https://doi.org/10.1117/12.2588944

KEYWORDS: Metalorganic chemical vapor deposition, Field effect transistors, Electronics, Transistors, Silicon carbide, Scattering, Atmospheric plasma, Silicon, Semiconductors, Roads

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Proceedings Article | 29 August 2017 Presentation + Paper

III-nitride terahertz photodetectors for the Reststrahlen gap of intersubband optoelectronics

R. Paiella, H. Durmaz, F. Sudradjat, D. Nothern, G. Brummer, W. Zhang, J. Woodward, T. Moustakas

Proceedings Volume 10353, 103530I (2017) https://doi.org/10.1117/12.2274040

KEYWORDS: Terahertz radiation, Quantum wells, Photodetectors, Optoelectronics, Optoelectronic devices, Absorption, Semiconductor optoelectronics, Phonons, Crystals, Polarization

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