Luke Nyakiti

Luke Nyakiti, MS. PhD. is currently Assistant Professor in the department of Marine Engineering and Technology at Texas A&M University – Galveston Campus. He is also an affiliated member of faculty in the Department of Material Science and Engineering at Texas A&M University – College Station. He obtained his Masters of Science degree in physics from Wichita State University. He received his doctorate degree from Texas Tech University in Mechanical Engineering in 2008, his research emphasis was on synthesis-structure relationship of III-nitrides semiconductor material systems, and the use of spectroscopic as well as transmission electron microscopic techniques to characterize the semiconductors. Upon graduating in 2008, he was a Postdoctoral researcher in the department of Mechanical Engineering where he studied nanocrystalline metallic structures of advanced metallic alloys synthesized by pulsed electrodeposition with improved hardness, strength, corrosion, wear resistant and superplasticity. He was awarded ASEE-NRL Postdoctoral Research Fellowship and was in residence at US Naval Research Laboratory - Washington D.C. where he took lead in synthesis-structural characterization and functional property relationship of two dimensional (Epitaxial Graphene) materials systems and their integration into device nanostructures e.g. graphene Field Effect Transistors. He was also responsible in research efforts designed at developing different approaches of homoepitaxial growth of SiC. He has authored or co-authored over 50 peer reviewed Journal publications in the areas of graphene, SiC, AlN, GaN,ScN, etc. He was recently awarded Japan Society of applied Physics (JSAP) outstanding paper award (2014).

Dr. Nyakiti teaches the following courses: Mechanics of materials, Fundamentals of metal Fatigue and Failure analysis, Material Science, and Advanced Characterization techniques in Transmission Electron Microscopy.

He is an active member in several national and international material science and engineering societies, such as Material Research Society (MRS), American Vacuum Society (AVS), American Chemical Society (ACS), American Physical Society (APS) and American Association for the Advancement of Science (AAAS).

EDUCATION

  • PhD in Mechanical Engineering, Texas Tech University – Texas.
  • MSc. in Physics, Wichita State University – Kansas.
  • BEd. Science in Physics and Mathematics – Egerton University.

RESEARCH INTERESTS AND IMPACTS

Dr. Nyakiti is involved in basic and applied research that focuses on engineered electronic materials that can easily be integrated into the existing silicon technology for a wide range of applications.

  • novel scalable large area (semiconducting) two-dimensional material system for energy and electronic applications, for example synthesis-structural characterization and functional property relationship of two dimensional (Epitaxial Graphene) materials systems and their integration into device nanostructures e.g. high speed RF graphene Field Effect Transistors.
  • process-structure and functional-property relationship of homoepitaxial growth of 4H- or 6H-SiC on variously varying off-cut SiC substrate, for high power switching devices utilizing chemical vapor deposition (CVD) systems. for robust high-voltage, high-power electronic device applications, that can benefit a variety of platforms eg in the Navy's aircraft carriers, submarines and prototypical all electric combat vehicles that is of interest to the Marine Corps, Army and the Air Force.
  • high k-dielectrics to improve electronic and optoelectronic properties of electronic devices;
  • advanced nanocrystalline metallic alloys synthesized by pulsed electrodeposition with improved hardness, strength, corrosion, wear resistant and superplasticity for catalytic and energy applications;
  • employing Optical, electro-mechanical, Electron microscopy and Spectroscopic Characterization techniques.

Selected Publications

         2015
  1. "Challenges to graphene growth on SiC (000-1): Substrate effects, hydrogen etching and growth ambient", Z. R Robinson, G. G Jernigan, M. Currie, J. K Hite, K. M Bussmann, L. O Nyakiti, N. Y Garces, A. Nath, M. V Rao, V. D Wheeler, R. L Myers-Ward, J. A Wollmershauser, B. N Feigelson, C. R Eddy, D K. Gaskill, Carbon, 81, 73 (2015)

    2014

  2. X. Cai, A. B. Sushkov, R. J. Suess, M. M. Jadidi, G. S. Jenkins, L. O. Nyakiti, R. L. Myers-Ward, S. Li, J. Yan, D. K. Gaskill, T. E. Murphy, H. D. Drew & M. S. Fuhrer, Sensitive room-temperature terahertz detection via the photothermoelectric effect in graphene,Nature Nanotechnology 9, 814–819 (2014).
  3. "Electronic transport properties of top-gated epitaxial-graphene nanoribbon field-effect transistors on SiC wafers", W. S. Hwang, Kristof Tahy, Pei Zhao, L. O Nyakiti, V. D Wheeler, R. L Myers-Ward, C. R Eddy Jr, D K. Gaskill, H. G. Xing, A. Seabaugh, D. Jena, Journal of Vacuum Science & Technology B, 32, (1) 012202 (2014)
  4. "Step edge influence on barrier height and contact area in vertical heterojunctions between epitaxial graphene and n-type 4H-SiC", MJ Tadjer, TJ Anderson, RL Myers-Ward, VD Wheeler, LO Nyakiti, Z Robinson, CR Eddy Jr, DK Gaskill, AD Koehler, KD Hobart, FJ Kub, Applied Physics Letters, 104, (7) 073508 (2014)
  5. "Plasma-based chemical modification of epitaxial graphene with oxygen functionalities", SC Hernández, VD Wheeler, MS Osofsky, GG Jernigan, VK Nagareddy, A Nath, EH Lock, LO Nyakiti, RL Myers-Ward, K Sridhara, AB Horsfall, CR Eddy Jr, DK Gaskill, SG Walton, Surface and Coatings Technology, 241, 8 (2014)
  6. "Membrane amplitude and triaxial stress in twisted bilayer graphene deciphered using first-principles directed elasticity theory and scanning tunneling microscopy", M Neek-Amal, P Xu, D Qi, PM Thibado, LO Nyakiti, VD Wheeler, RL Myers-Ward, CR Eddy Jr, DK Gaskill, FM Peeters, Phys. Rev. B 90, (6) 064101 (2014)
  7. "Spontaneous Conversion of Basal Plane Dislocations in 4° Off-Axis 4H–SiC Epitaxial Layers", R. L Myers-Ward, N. A Mahadik, V. D Wheeler, L. O Nyakiti, R. E Stahlbush, E. A Imhoff, K. D Hobart, CR Eddy Jr, D Kurt Gaskill, Crystal Growth and Design, 14 (11) 5331 (2014)
  8. "Multilayer graphene, Moiré patterns, grain "boundaries and defects identified by scanning tunneling microscopy on the m-plane, non-polar surface of SiC", P Xu, D Qi, JK Schoelz, J Thompson, PM Thibado, VD Wheeler, LO Nyakiti, RL Myers-Ward, CR Eddy, DK Gaskill, M Neek-Amal, FM Peeters, Carbon, 80, 75 (2014)

    2013

  9. "Graphene Manipulation on 4H-SiC (0001) Using Scanning Tunneling Microscopy", P. Xu, M. L Ackerman, S. D Barber, J. K Schoelz, D. Qi, P. M Thibado, V. D Wheeler, L. O Nyakiti, R. L Myers-Ward, C. R Eddy Jr, D K. Gaskill, Japanese Journal of Applied Physics 52 (3R), 035104, (2013)
  10. "Epitaxial Growth of III–Nitride/Graphene Heterostructures for Electronic Devices", N. Nepal, V. D Wheeler, T. J Anderson, F. J Kub, M. A Mastro, R. L Myers-Ward, S. B Qadri, J. A Freitas, S. C Hernandez, L. O Nyakiti, S. G Walton, K.Gaskill, C. R Eddy Jr, Appl. Phys. Express 6 (6) 061003 (2013)
  11. "Competing scanning tunneling microscope tip-interlayer interactions for twisted multilayer graphene on the a-plane SiC surface", P Xu, ML Ackerman, SD Barber, JK Schoelz, PM Thibado, VD Wheeler, LO Nyakiti, RL Myers-Ward, CR Eddy Jr, DK Gaskill, Surface Science, 617, 113-117 (2013)
  12. "Chemically-Resolved Interface Structure of Epitaxial Graphene on SiC(0001)", J. D. Emery, B. Detlefs, H. J. Karmel, L. O. Nyakiti, D. K. Gaskill, M. C. Hersam, J. Zegenhagen, M. J. Bedzyk, Physical Review Letters, 111, 215501 (2013)
  13. "Nucleation of In-grown Stacking Faults and Dislocation Half-loops in 4H-SiC Epitaxy", M. Abadier, R. L. Myers-Ward, N. A. Mahadik, R. E. Stahlbush, V. D. Wheeler, L. O. Nyakiti, C. R. Eddy, Jr., D. K. Gaskill, H. Song, T. S. Sudarshan, Y. N. Picard and M. Skowronski, Journal of Applied Physics, 114, 123502 (2013) DOI: 10.1063/1.4821242
  14. "Epitaxial growth of III-Nitride/graphene Heterostructures for Electronic Devices", N. Nepal, V. D. Wheeler, T. J. Anderson, F. J. Kub, M. A. Maestro, R. L. Myers-Ward, S. B. Qadri, J. A. Freitas, S. C. Hernandez, L. O. Nyakiti, S. G. Walton, K. Gaskill, C. R. Eddy, Jr. Appl. Phys. Express 6, 061003 (2013)
  15. "Graphene FETs for Zero-Bias Linear Resistive FET Mixers", J. S. Moon, H.-C. Seo, M. Antcliffe, D. Le, C. McGuire, A. Schmitz, L. O. Nyakiti, D. K. Gaskill, P. M. Campbell, K.-M. Lee, and P. Asbeck, IEEE Electron Device Letters, 34, (3), 465 (2013)
  16. "Graphene manipulation on 4H-SiC(0001) using scanning tunneling microscopy, P. Xu, M. L. Ackerman, S. D. Barber, J. K. Schoelz, D. Qi, P. M. Thibado, V. D. Wheeler, L. O. Nyakiti, R. L. Myers-Ward, C. R. Eddy, Jr., and D. K. Gaskill Japanese Journal of Applied Physics52, 035104 (2013).
  17. "Lateral Graphene Heterostructure Field-Effect Transistor", J.S. Moon, Hwa-chang Seo, F. Stratan, M. Antcliffe, A. Schmitz, R. S. Ross, A. A. Kiselev, V. D. Wheeler, L. O. Nyakiti, D. K. Gaskill, L. Kang-Mu, P. M. Asbeck, Electron Device Letters, IEEE 34, (9) ,1190–1192,(2013) DOI: 10.1109/LED.2013.2270368

    2012

  18. "Enabling Graphene based Technologies: Towards Wafer Scale Production of Epitaxial Graphene", L.O. Nyakiti, V.D. Wheeler, N.Y Garces, R.L. Myers-Ward, C.R. Eddy, Jr., and D.K. Gaskill, Special issue, MRS Bulletin Volume 37, December 2012
  19. "Graphene FET – Based Zero-Bias RF to Millimeter – Wave Detection", J. Moon, H.-C. Seo, M. Antcliffe, S. Lin, C. McGuire, D. Le, L. O. Nyakiti, D. K. Gaskill, P. M. Campbell, K.-M. Lee, P. Asbeck IEEE Electron Device Letters 33, 10, 1357, 2012
  20. "Vertical conduction mechanism of the epitaxial graphene/n-type 4H-SiC heterojunction at cryogenic temperatures", M. J. Tadjer,T. J. Anderson, K. D. Hobart, L. O. Nyakiti, V. D. Wheeler, R. L. Myers-Ward, D. K. Gaskill, C. R. Eddy, Jr., F. J. Kub, and F. Calle, Applied Physics Letters 100, 193506 (2012).
  21. "Bilayer Graphene Grown on 4H-SiC(0001) Step-Free Mesas",L.O. Nyakiti, R. L. Myers-Ward, V. D. Wheeler, E. A. Imhoff, F.J. Bezares, H. Chun, J. D. Caldwell, A. L. Friedman, B. R. Matis, J. W. Baldwin, P. M. Campbell, J. C. Culbertson, C. R. Eddy, G. G. Jernigan and D. K. Gaskill, Nano letters,12 (4), 1749–1756 (2012)
  22. "Fluorine functionalization of epitaxial graphene for uniform deposition of thin high-? dielectrics", V. Wheeler, N. Garces, L. Nyakiti, R. Myers-Ward, G. Jernigan, J. Culbertson, C. Eddy Jr., D. K. Gaskill, Carbon, 50, 6, 2307, 2012
  23. "Fabrication of top-gated epitaxial graphene nanoribbon FETs using hydrogen-silsesquioxane", W. S. Hwang, K. Tahy, L. O. Nyakiti, V. D. Wheeler, R. L. Myers-Ward, C. R.Eddy, Jr., D. Kurt Gaskill, H. G. Xing, A. Seabaugh, D. Jena, J. Vac. Sci. Technol. B, 30, 3, 03D104 - 03D104-4 , 2012
  24. "Bilayer Graphene by Bonding CVD Graphene to Epitaxial Graphene", G. G. Jernigan, T. J. Anderson, J. T. Robinson, J. D. Caldwell, J. C. Culbertson, M. G. Ancona, V. D. Wheeler, L. O. Nyakiti, R. Myers-Ward, A. L. Davidson, A. L. Friedman, P. M. Campbell, D. Kurt Gaskill, Journal of Vacuum Science and Technology B, 30 (3) 03D110 (2012)

    2011

  25. "Observations on C-face SiC Graphene Growth in Argon", D.K. Gaskill, J.K. Hite, J.C. Culbertson, G.G. Jernigan, J.L. Tedescso, L.O. Nyakiti, V.D. Wheeler, R.L. Myers-Ward, N.Y. Garces and C.R. Eddy, Jr., Materials Science Forum679-680, 789-792 (2011).
  26. "Secondary electron dopant contrast imaging of compound semiconductor junctions", S. Chung, V. Wheeler, R.L Myers-Ward, L. O Nyakiti, C. R Eddy, D K. Gaskill, M. Skowronski, Y. N Picard Journal of Applied Physics 110 (1), 014902 (2011)
  27. "Growth of 4H- and 3C-SiC Epitaxial Layers on 4H-SiC Step-Free Mesas" R. L. Myers-Ward, L. O. Nyakiti, J. K. Hite, O. J. Glembocki, F. J. Bezares, J. D. Caldwell, E. A. Imhoff, K. D. Hobart, J. C. Culbertson, Y. N. Picard, V. D. Wheeler, C. R. Eddy, D K. Gaskill, Materials Science Forum 679, 119-122 (2011)

    2010 - 2006

  28. "Transmission Electron Microscopy study of defects in AlN crystals with rough and smooth surface grains",L. Nyakiti, J. Chaudhuri, Z. Gu, J. H. Edgar, Journal of Crystal Growth, 312, 3479 (2010).
  29. "Anomalies in Hall-Petch Strengthening for Nanocrystalline Au-Cu Alloys Below 10 nm Grain Size", A.F. Jankowski and L.O. Nyakiti, Surface and Coatings Technology 205 1398 (2010)
  30. "Characterization of strain-rate sensitivity and grain boundary structure in nanocrystalline gold-copper alloys", L. O. Nyakiti, A. Jankowski, Metallurgical and Materials Transactions A, Metallurgical and Materials Transactions A, 41 838 (2010)
  31. "Modeling of the effects of different substrate materials on the residual thermal stresses in the aluminum nitride crystal grown by sublimation", R. G. Lee, L. Nyakiti, A. Idesman, J. Chaudhuri, J. App. Phys. 105, 033521 (2009).
  32. "High –Resolution Electron Microscopy Characterization of nanocrystalline Grain Boundaries in Gold – Copper Alloys", L. O. Nyakiti, A. Jankowski, J. Chaudhuri, Thin film Solids, 517, 1182 (2008).
  33. "Growth of GaN Nanowires on Epitaxial GaN", D. Aurongzeb, D.Y. Song, G. Kipshidze, B. Yavich, L. Nyakiti, R. Lee, J. Chaudhuri, H. Temkin and M. Holtz, J. of Electr. Matrls. 37, 8, 1076 (2008).
  34. "Native oxide and hydroxide and their implications for bulk AlN crystal growth", J.H. Edgar, L. Du, L. Nyakiti, and J. Chaudhuri, J. Cryst. Growth. 310, 17, 4002– 4006 (2008).
  35. "Thermal oxidation of single crystal aluminum nitride – a high resolution transmission electron microscopy study", J. Chaudhuri, R.G. Lee, L.O. Nyakiti, Z. Gu, J.H. Edgar, and P. Li, Materials Lett. 62, 16, 2465-2468 (2008).
  36. "Transmission electron microscopy study of defect-selective etched (010) ScN crystals", J. Chaudhuri, R.G. Lee, L. Nyakiti, J. Armstrong, Z. Gu, J.H. Edgar, and J.G. Wen, Mater. Lett. 62 27 (2008).
  37. "Thermal oxidation of single crystalline aluminum nitride", J. Chaudhuri, L. Nyakiti, R.G. Lee, Z. Gu, J.H. Edgar, and J.G. Wen, Mater. Charact. 58, 672 (2007).
  38. "Modeling of residual thermal stresses for aluminum nitride crystal growth by sublimation", R. G. Lee, A. Idesman, L. Nyakiti, and J. Chaudhuri, J. App. Phys . 102, 6, 063525 (2007).
  39. "Molybdenum Nitride nanoparticles - High-Resolution Transmission Electron Microscopy study", J. Chaudhuri, L. Nyakiti, R. G. Lee, Y. Ma, P. Li, Q. L. Cui, L. H. Shen, Journal of Materials Letters.61 26,4763 (2007).
  40. "Defect selective etching of scandium nitride crystals", Z. Gu, J.H. Edgar, D.W. Coffey, J. Chaudhuri, L. Nyakiti, R.G. Lee, and J.G. Wen, J. Cryst. Growth, 293, 2, 242 (2006).
Luke Nyakiti

Luke O. Nyakiti M.S. PhD.
Assistant Professor
Department of Marine Engineering Technology
Bldg: 3027, Room 214
Texas A&M University - Galveston Campus
P.O. Box 1675
Galveston, Texas 77553.

Also, Assistant Professor,
Department of Material Science and Engineering,
Dwight Look College of Engineering,
Texas A&M University,
College Station, TX 77843-3003,

Phone: 409-740-4505
Fax: 409-741-7153
E-mail: nyakitil@tamu.edu
http://engineering.tamu.edu/materials/people/lnyakiti