My research includes the study of the structural, electronic, optical and optoelectronic properties of semiconductors and nanostructures, emphasizing the relationships among defects, electronic structure, and device performance. Surface and interface effects (for example chemical reactions at solid-liquid interfaces) are also of interest. I am further interested in understanding fundamental interactions between biological molecules, particularly how solvation effects play a major role in binding and cellular function.
My research employs both experimental and computational techniques. The theoretical work utilizes primarily ab initio electronic structure calculations and molecular dynamics simulations, including density functional theory and quantum Monte Carlo, among other methods. The experimental tools include various optical spectroscopies (absorption, photocurrent, electroreflectance, FTIR, …), x-ray spectroscopies (XAS, XANES, EXAFS, XRD, …), atomic force microscopy, chemical force microscopy, electron microscopy (TEM, SEM, LEEM), and other techniques.
Honors and Awards
- Global Security Principal Directorate Silver Award, LLNL, 2008
- Lawrence Fellowship, LLNL, 2006-2008
- Hertz Foundation Graduate Research Fellowship, 1999-2004
- Electronic Materials Conference Best Student Paper Award, 2004
- Ticona Senior Thesis Award, 1999
- Microscopy Society of America Undergraduate Research Scholarship, 1998
- Radiation Detection Materials
Åberg, D., P. Erhart, A.J. Williamson, and V. Lordi, “Intrinsic point defects in aluminum antimonide,” Physical Review B 77(16), 165206 (2008).
- Vo, T.T.M., A.J. Williamson, V. Lordi, G. Galli, “Atomistic design of thermoelectric properties of silicon nanowires,” Nano Letters 8(4), 1111 (2008).
- Lordi, V., D. Åberg, P. Erhart, and K.J. Wu, “First principles calculation of point defects and mobility degradation in bulk AlSb for radiation detection application,” Proc. SPIE, Vol. 6706, 67060O (2007).
- Tringe, J.W., A.M. Conway, T.E. Felter, W.J. MoberlyChan, J. Castelaz, V. Lordi, Y. Xia, C. Stevens, and C. Wetzel, “Radiation effects on InGaN quantum wells and GaN simultaneously probed by ion beam-induced luminescence,” IEEE Transactions on Nuclear Science, (2008), accepted.
Lordi, V., H.B. Yuen, S.R. Bank, M.A. Wistey, S. Friedrich, and J.S. Harris, “Nearest neighbor distributions in GaInNAs(Sb) upon annealing,” Physical Review B 71(12), 125309 (2005).
- Lordi, V., H. Yuen, S. Bank, and J.S. Harris, “Quantum confined Stark effect of GaInNAs(Sb) quantum wells at 1300-1600 nm,” Applied Physics Letters 85(6), 902 (2004). [Accepted without revision]
- Lordi, V., V. Gambin, S. Friedrich, T. Funk, T. Takizawa, K. Uno, and J.S. Harris, “Nearest-neighbor configuration in (GaIn)(NAs) probed by x-ray absorption spectroscopy,” Physical Review Letters 90(14), 145505 (2003). [Accepted without revision]
- Lordi, V., H. Yuen, and J.S. Harris, “Electroabsorption Properties of GaInNAs(Sb) Quantum Wells at 1300nm and Beyond,” Materials Research Society 2003 Fall Meeting, Symposium Z (Boston, 2003).
- Harris, J.S., Jr., M. Wistey, S. Bank, V. Lordi, L. Goddard, H. Bae, and H. Yuen, “Long-Wavelength Dilute Nitride-Antimonide Lasers” in Dilute Nitride (III-V) Semiconductors: Physics and Technology, M. Henini, ed. (Elsevier: New York, 2005). [Book chapter]
- Harris, J.S., Jr., H. Yuen, M. Wistey, S. Bank, V. Lordi, T. Gugov, H. Bae, and L. Goddard, “MBE Growth and Characterization of Dilute Nitride III-V Alloys” in Dilute Nitride (III-V) Semiconductors: Physics and Technology, M. Henini, ed. (Elsevier: New York, 2005). [Book chapter]
- Bank, S.R., H.B. Yuen, M.A. Wistey, V. Lordi, H.P. Bae, and J.S. Harris, Jr., “Effects of growth temperature on the structural and optical properties of 1.55 um GaInNAsSb quantum wells grown on GaAs,” Applied Physics Letters 87, 021908 (2005).
- Bank, S.R., M.A. Wistey, H.B. Yuen, V. Lordi, V.F. Gambin, and J.S. Harris Jr., “Effects of Antimony and Ion Damage on Carrier Localization in molecular-beam-epitaxy-Grown GaInNAs,” Journal of Vacuum Science and Technology B 23(3), 1320 (2005).
- Bank, S.R., M.A. Wistey, L.L. Goddard, H.B. Yuen, V. Lordi, and J.S. Harris, “Low Threshold, Continuous Wave, 1.5 um GaInNAsSb Lasers Grown on GaAs,” IEEE Journal of Quantum Electronics 40(6), 656 (2004).
- Gambin, V., V. Lordi, W. Ha, M. Wistey, T. Takizawa, K. Uno, S. Friedrich, and J.S. Harris, “Structural Changes on Anneal of MBE Grown (Ga,In)(N,As) as Measured by X-ray Absorption Fine Structure,” Journal of Crystal Growth 251(1-4), 408 (2003).
- Ha, W., V. Gambin, S. Bank, M. Wistey, H. Yuen, V. Lordi, S. Kim, and J.S. Harris, “Long Wavelength GaInNAs(Sb) Lasers on GaAs,” IEEE Journal of Quantum Electronics 38, 1260 (2002).
- Quantum Dots and Type II Quantum Wells
Hatami, F., W.T. Masselink, V. Lordi, J.S. Harris, Jr., “Green emission from InP-GaP quantum-dot light-emitting diodes,” Photonics Technology Letters 18(7), 895 (2006).
- Yang, H., V. Lordi, and J.S. Harris, “Photoluminescence and electroabsorption in GaNAs/GaAsSb heterojunctions,” Electronics Letters 42(1), 3572 (2006).
- Hatami, F., V. Lordi, J.S. Harris, H. Kostial, W.T. Masselink, “Red light-emitting diodes based on InP/GaP quantum dots,” Journal of Applied Physics 97, 096106 (2005). [Featured in Virtual Journal of Nanoscale Science & Technology 11(17), 2005.]
- Hatami, F., V. Lordi, J.S. Harris, and W.T. Masselink, “Light-emitting diodes based on InP quantum dots in GaP(100),” Proc. SPIE Int. Soc. Opt. Eng. 5739, 86 (2005).
Lordi, V., N. Yao, and J. Wei, “Method for Supporting Platinum on Single-Walled Carbon Nanotube for a Selective Hydrogenation Catalyst,” Chemistry of Materials 13(3), 733 (2001).
- Lordi, V. and N. Yao, “Molecular Mechanics of Binding in Carbon Nanotube-Polymer Composites,” Journal of Materials Research 15(12), 2770 (2000).
- Lordi, V., N. Yao, and J. Wei, “Single-Walled Carbon Nanotube-Supported Platinum Catalyst for Selective Hydrogenation of an alpha,beta-Unsaturated Aldehyde,” Microscopy & Microanalysis 5 Suppl. (2), 142 (1999).
- Lordi, V., S.X.C. Ma, and N. Yao, “Towards probing pentagons on carbon nanotube tips,” Surface Science Letters 421(1/2), L150 (1999).
- Lordi, V., N. Yao, and J. Wei, “Single-Walled Carbon Nanotube-Supported Platinum Catalyst for Selective Hydrogenation of an alpha,beta-Unsaturated Aldehyde,” Proceedings of Materials Research Society 1999 Fall Meeting, Symposium U (Boston, 1999).
- Lordi, V. and N. Yao, “Radial compression and controlled cutting of carbon nanotubes,” Journal of Chemical Physics 109(6) 2509 (1998).
- Lordi, V., S.X.C. Ma, and N. Yao, “Conical structure of carbon nanotube tips,” in Electron Microscopy 1998: Proceedings of the 14th ICEM, eds. H.A.C. Benavides and M.J. Yacamón (Institute of Physics Publishing, Bristol, 1998), vol. III, p. 117.
- Lordi, V. and N. Yao, “HRTEM of Initial Oxidation of Carbon Nanotube Tips,” Microscopy and Microanalysis 3 Suppl. (2), 421 (1997).
- Yao, N. and V. Lordi, “Carbon nanotube caps as springs: Molecular dynamics simulations,” Physical Review B 58(19), 12649 (1998).
- Yao, N., V. Lordi, S.X.C. Ma, E. Dujardin, A. Krishnan, M.M.J. Treacy, and T.W. Ebbesen, “Structure and oxidation patterns of carbon nanotubes,” Journal of Materials Research 13(9), 2432 (1998). [Special issue on carbon nanotubes.]
- Yao, N. and V. Lordi, “Young’s modulus of single-walled carbon nanotubes,” Journal of Applied Physics 84(4), 1939 (1998).
- Yao, N. and V. Lordi, “Nanomechanics of carbon nanotubes,” in Electron Microscopy 1998: Proceedings of the 14th International Congress on Electron Microscopy, eds. H.A.C. Benavides and M.J. Yacamón (Institute of Physics Publishing, Bristol, 1998), vol. III, p. 73.