Biography

My current work is on the development of the sodium flux growth technique to enable bulk growth of gallium nitride. This growth method allows lower pressure growth of single crystal gallium nitride than other major bulk techniques (e.g. the ammonothermal technique, high nitrogen pressure) while also being capable of producing higher structural quality crystals than heteroepitaxially grown hydride vapor phase epitaxy GaN.

Publications:

1. M. A. Alreesh, P. Von Dollen, T. F. Malkowski, T. Mates, H. Albrithen, S. Nakamura, J. S. Speck, Investigation of Oxygen and Other Impurities and Their Effect on the Transparency of a Na Flux Grown GaN Crystal. Journal of Crystal Growth. Vol 508, pg 50-57. DOI: 10.1016/j.jcrysgro.2018.12.018 (2019)

2. T. F. Malkowski, J. S. Speck, S. P. DenBaars, S. Nakamura. An Exploratory Study of Acidic Ammonothermal Growth in a TZM Autoclave at High Temperatures. Journal of Crystal Growth. Vol 499, pg 85-89. DOI: 10.1016/j.jcrysgro.2018.07.025 (2018)

3. S. Griffiths, S. Pimputkar, J. Kearns, T. F. Malkowski, M. F. Doherty, J. S. Speck, S. Nakamura. Growth Kinetics of Basic Ammonothermal Gallium Nitride Crystals. Journal of Crystal Growth. Vol 501, pg 74-80. DOI: 10.1016/j.jcrysgro.2018.08.028 (2018)

4. A.-C. Kimmel, T. F. Malkowski, S. Griffiths, B. Hertwek, T. G. Steigerwald, L. P. Freund, S. Neumeier, M. G¨oken, J. S. Speck, E. Schluecker. High-Temperature Corrosion of Inconel R Alloy 718, Haynes R 282 Alloy and CoWAlloy1&2 in Supercritical  \Ammonia/Ammonium Chloride Solution. Journal of Crystal Growth. Vol 498, pg 289-300. DOI: 10.1016/j.jcrysgro.2018.06.018 (2018)

5. T. F. Malkowski, S. Pimputkar, J. S. Speck, S. P. DenBaars, S. Nakamura. Acidic Ammonothermal Growth of Gallium Nitride in a Liner-Free Molybdenum Alloy Autoclave. Journal of Crystal Growth. Vol 456, pg  21-26. DOI: 10.1016/j.jcrysgro.2016.07.045 (2016)

6. S. Pimputkar, T. F. Malkowski, S. Griffiths, A. Espenlaub, S. Suihkonen, J. S. Speck, S. Nakamura. Stability of Materials in Supercritical  Ammonia Solutions. Journal of Supercritical Fluids. Vol 110, pg 193-229.  DOI: 10.1016/j.supflu.2015.10.020 (2016)

7. J. J. Adams, E. B. Duoss, T. F. Malkowski, J. A. Lewis, J. T. Bernhard. Design of Spherical Meanderline Antennas. Proceedings of the 2011 IEEE Antennas and Propagation Society International Symposium and UNSC/URSI National Radio Science Meeting. Pg 765-768 (2011)

8. J. J. Adams, E. B. Duoss, T. F. Malkowski, M. J. Motala, B. Y. Ahn, R. G. Nuzzo, J. T. Bernhard, J. A. Lewis. Conformal Printing of Electrically Small Antennas on Three-Dimensional Surfaces. Advanced Materials, Vol 23, issue 11, pg 1335-1340. DOI: 10.1002/adma.201003734. (2011)

9. J. J. Adams, S. C. Slimmer, T. F. Malkowski, E. B. Duoss, J. A. Lewis, J. T. Bernhard. Comparison of Spherical Antennas Fabricated via Conformal Printing: Helix, Meanderline, and Hybrid Designs. IEEE Antennas and Wireless Propagation Letters, Vol 10, pg 1425-1428. DOI 10.1109/LAWP.2011.2178999 (2011)

10. B. Y. Ahn, S. B. Walker, S. C. Slimmer, A. Russo, A. Gupta, S. Kranz, E.B. Duoss, T. F. Malkowski, J. A. Lewis. Planar and Three-Dimensional Printing of Conductive Inks. Journal of Visualized Experiments, issue 58. DOI: 10.3791/3189 (2011)