Nanotechnology, the fabrication and manipulation of structures on the nanometer scale, has lead to the observation of new physical behavior and the development of new technologies. My research involves the fabrication, characterization, and study of a wide variety of individual nanostructures and their arrays.
Materials of interest include: semiconductors, ferro-electrics and ferro-magnets, superconductors and polymers through nanotubes. In particular, I am interested in well-ordered arrays of nanostructures because such arrays will show new collective properties in much the same way that crystals show new properties compared with the properties of the individual constituent atoms or molecules from which they are made.
Fabrication techniques used in my lab include: lithography involving electron and ion-beams as well as scanning probe microscopy, and deposition from thermal and electron-beam evaporation and sputtering through molecular beam epitaxy. Characterization involves various types of scanning probe microscopies, x-ray diffraction, optical techniques including, UV-Vis, photoluminescence, various infrared techniques; scanning electron microscopy (SEM) and conventional and high-resolution transmission electron microscopy (TEM). Collective behavior etc. are studied using low-temperature magneto-transport available at OU and magnetometry, terahertz spectroscopy, Brillouin scattering, low-temperature magnetic force microscopy, and other more exotic techniques available through National Labs and various collaborations.
Representative Publications:
- J.C. Keay, P.R. Larson, K.L. Hobbs, M.B. Johnson, J.R. Kirtley, O.M. Auslaender, and K.A. Moler, "Sequential vortex hopping in an array of artificial pinning centers," Phys. Rev. B 80, 165421 (2009).
- Z. Tian, R. Q. Yang, T. D. Mishima, M. B. Santos, R. T. Hinkey, M. E. Curtis, and M. B. Johnson, "InAs-based interband cascade lasers near 6mm," Electron. Lett. 45, 48 (2009);
- H. Wang, R.P. Nair, M. Zou, P.R. Larson, A.L. Pollack, K.L. Hobbs, M.B. Johnson, and O. K. Awitor, "Friction Study of a Ni Nanodot-patterned Surface," Tribology Lett. 28, 183 (2007).
- Y. Chen, M. Kim, G.D. Lian, M.B. Johnson, and X. Peng, "Side Reactions in Controlling the Quality, Yield, and Stability of High Quality Colloidal Nanocrystals," J. Am. Chem. Soc. 127, 13331 (2005).
- Z.K. Wang, H.S. Lim, H.Y. Liu, S.C. Ng, M.H. Kuok, L.L. Tay, D.J. Lockwood, M.G. Cottam, K.L. Hobbs, P.R. Larson, J.C. Keay, G.D. Lian, and M.B. Johnson, "Spin Waves in High-aspect-ratio Nickel Nanorings," Phys. Rev Lett. 94, 137208 (2005).
- D.G. Cooke, F.A. Hegmann, Y.I. Mazur, W.Q. Ma, X. Wang, Z.M. Wang, G.J. Salamo, M. Xiao, T.D. Mishima. M.B. Johnson, "Anisotropic photoconductivity of InGaAs quantum dot chains measured by terahertz pulse spectroscopy," Appl. Phys. Lett. 85, 3839, (2004).