Logo
MyQC BlackBoard CUNYfirst The Graduate Center

The roots of education are bitter, but the fruit is sweet.

Aristotle

Faculty

Photo
Igor L. Kuskovsky, Professor & Chair

Experimental Condensed Matter/Materials Science

girok.suoksvykq@.cucyne.ud
(718) 997-3367, SB B206
- Ph.D. in Applied Physics/Solid State, 1998
Department of Applied Physics & Applied Mathematics, Columbia University, New York, NY
- M.S. in Materials Science and Engineering, 1995
HKSM, Columbia University, New York, NY
PHYS 225 - Solid State Electronics
Science and technology at nanoscale have numerous opportunities both for fundamental research and new applications. Quantum dots, nanocrystals, nanowires, and nanorods are among the most important building blocks of nano-photonic devices. Therefore, the understanding of underlying fundamental physical phenomena in such structures is very important for future progress. We are interested in fundamental properties of wide bad gap nanostructured materials, particularly those with type-II band alignment, with potential application in photo-detection, quantum information, and biomedical field. Type-II heterostructures have several substantial advantages over type-I systems in that that they suppress non-radiative Auger recombination, and their emission can be controlled by external means such as intensity of excitation, electric and magnetic fields. We particularly focused on properties of epitaxial ZnTe/ZnSe quantum dot multilayers and related alloys, type-II colloidal core-shell nanoparticles, and II-VI nanowires.

In the ZnTe-ZnSe systems holes are strongly confined within ZnTe-rich quantum dots, whereas electrons locate in ZnSe barriers, and only weakly attracted to holes via the Coulomb interaction, forming the spatially indirect (type-II) excitons. It is important that QDs in this system coexist with Ten isoelectronic centers, and a smooth transition between these two different species is indicated by experimental results. Therefore, QDs here are formed by continuing enlargement of Ten/Se isoelectronic centers. In magnetic field this system exhibits one of the most interesting quantum phenomena - so-called optical Aharonov-Bohm Effect, for which we observed photoluminescence intensity as well as energy oscillations within the same sample, experimentally, for the first time. The samples are grown by Prof. M. C. Tamargo’s group of The City College. Other similar systems, for instance ZnTe/ZnCdSe multilayers of submonolayer type-II QDs, can be used as intermediate band material in QD-based intermediate-band solar cells; such solar cells can have efficiency as high as 63% under full solar concentration. We are interested in both material properties and application of this material system.

In addition to epitaxial quantum dots we, currently, are working on several aspects of optical properties of colloidal ZnO nanostructures, including core-shell systems. We have shown that quantum size effects can be achieved in ZnO nanorods, and we continue to investigate the role of dielectric confinement on ZnO nanorods optical properties, as it is important for 1-D systems. We investigate also the role of morphology on the optical properties of ZnO nanostrutures, including origin of the green band. Recently, we began growing ZnO nanowires using in-house built CVD system. 

We are also working in application of type-II structures for high sensitivity biological detectors. This work is in collaboration with Prof. Mourokh and Prof. H. Matsui of Hunter College. The pathogen diagnostics is constrained by a variety of challeneges that compromise essential elements of detection. Our approach uses unique optical properties of type-II colloidal fluorescent quantum dots.
Books and Book Chapters
  1. I. R. Sellers, I. L. Kuskovsky, A. O. Govorov, B. D. McCombe, Optical Aharonov-Bohm Effect in Type-II Quantum Dots, in Book: “Physics of Quantum Rings”, V. Fomin (Editor), Springer, Series: NanoScience and Technology, XXIV 487 p. (2014).
  2. G. F. Neumark, I. L. Kuskovsky, and H. Jiang (editors), Wide Bandgap Light Emitting Materials and Devices, Wiley-VCH, 1st Edition, 216 Pages (2007).
  3. Y. Gu, I. L. Kuskovsky, and G. F. Neumark, ZnSeTe Rediscovered: From Isoelectronic Centers to Quantum Dots, p. 147-176 in Wide Bandgap Light Emitting Materials And Devices, G. F. Neumark, I. L. Kuskovsky, and H. Jiang (editors), Wiley-VCH, 1st Edition, 216 Pages (2007).
  4. I. L. Kuskovsky, G. F. Neumark, and Y. Gong, Doping Aspects Of Zn-Based Wide-Band-Gap Semiconductors, in Springer Handbook of Electronic and Photonic Materials, S. Kasap, P. Capper (Eds.) Speringer-Verlag, Part D, p. 843 (2006).
Journals
  1. S. Dhomkar, U. Manna, I. C. Noyan, M. C. Tamargo, and I. L. Kuskovsky, Vertical correlation and miniband formation in submonolayer Zn(Cd)Te/ZnCdSe type-II quantum dots for intermediate band solar cell application, Appl. Phys. Lett. 103, 181905 (2013)
  2. H. Ji, B. Roy, S. Dhomkar, R. T. Moug, M. C. Tamargo A. Wang,  and I. L. Kuskovsky, Tuning Between Quantum-Dot- and Quantum-Well-Like Behaviors in Type II ZnTe Submonolayer Quantum Dots by Controlling Tellurium Flux During MBE Growth, J. Electr. Mat. 42, 3297- 3302 (2013)
  3. S. Dhomkar, U.Manna, L.Peng, R.Moug, I.C.Noyan, M.C. Tamargo, and I. L. Kuskovsky, Feasibility of submonolayer ZnTe/ZnCdSe quantum dots as intermediate band solar cell material system, Sol. Ener. Mater. Sol. Cells 117, 604–609 (2013)
  4. S. Dhomkar, I. L. Kuskovsky, U. Manna, I.C. Noyan, and M.C. Tamargo, Optimization of growth conditions of type-II Zn(Cd)Te/ZnCdSe submonolayer quantum dot superlattices for intermediate band solar cells, J. Vac. Sci. Technol. B 31, 03C119-1-7 (2013).
  5. B. Roy, H. Ji, S. Dhomkar, F.J. Cadieu, L. Peng, R. Moug, M.C. Tamargo, and I.L. Kuskovsky, Distinguishability of stacks in ZnTe/ZnSe quantum dots via spectral analysis of Aharonov-Bohm oscillations, Eur. Phys. J. B, 86, 31-1-5 (2013).
  6. B. Roy, H. Ji, S. Dhomkar, F. J. Cadieu, L. Peng, R. Moug, M. C. Tamargo, Y. Kim, D. Smirnov, and I. L. Kuskovsky, Enhancement and Narrowing of the Aharonov-Bohm Oscillations due to Built-in Electric Field in Stacked Type-II ZnTe/ZnSe Quantum Dots: Spectral Analysis, Phys. Rev. B, 86, 165310 (2012)
  7. U. Manna, Q. Zhang, S. Dhomkar, I. F. Salakhutdinov, M. C. Tamargo, I. C. Noyan, G. F. Neumark, and I. L. Kuskovsky, Radiative transitions in stacked type-II ZnMgTe quantum dots embedded in ZnSe, J. Appl. Phys. 112, 063521 (2012).
  8. B. Roy, H. Ji, S. Dhomkar, F. J. Cadieu, L. Peng, R. Moug, M. C. Tamargo, and I. L. Kuskovsky, Determination of excitonic size with sub-nanometer precision via excitonic Aharonov-Bohm effect in type-II quantum dots, Appl. Phys. Lett. 100, 213114 (2012)
  9. U. Manna, I. C. Noyan, Q. Zhang, I. F. Salakhutdinov, K. A. Dunn, S. W. Novak, R. Moug, M. C. Tamargo, G. F. Neumark, and I. L. Kuskovsky, Structural properties and spatial ordering in multilayered ZnMgTe/ZnSe type-II quantum dot structures, J. Appl. Phys. 111, 033516 (2012)
  10. Q. Zhang, A. Shen, I. L. Kuskovsky, M. C.Tamargo, Role of magnesium in band gap engineering of sub-monolayer type-II ZnTe quantum dots embedded in ZnSe, J. Appl. Phys. 110, 034302 (2011)
  11. B. Roy, A. Shen, M. C. Tamargo, and I. L. Kuskovsky,  Effects of Varying MBE Growth Conditions on Layered Zn-Se-Te Structures, J. Electr. Mat., 40, 1775-1780 (2011)
  12. I. L. Kuskovsky, Y. Gong, G. F. Neumark, and M. C. Tamargo, Photoluminescence and Magneto-Optical Properties of Multilayered Type-II ZnTe/ZnSe Quantum Dots, Supperlattices and Microstructures, 47, 87-92 (2010)
  13. V. V. Volkov, Y. Zhu, I. L. Kuskovsky, V. A. Shuvayev, F. Xu, H. Matsui, TEM Characterization and Optical Properties of Hetero-Structured ZnO/CdS Quantum Dots with Long Exciton Lifetime, Microsc. Microanal. 16 (Suppl. 2), 1684-1685 (2010)
  14. F. Xu, V. Volkov, Y. Zhu, H. Bai,  A. Rea, N. V. Valappil, X. Gao,  I. L. Kuskovsky, and H. Matsui, Long Electron-Hole Separation of ZnO-CdS Core-Shell Quantum Dots, J. Phys. Chem. B, 113, 19419–19423 (2009).
  15. V. A. Shuvayev, I. L. Kuskovsky, L. I. Deych, Y. Gu, Y. Gong, G. F. Neumark, M. C. Tamargo, and A. A. Lisyansky, Dynamics of the radiative recombination in cylindrical nanostructures with type-II band alignment, Phys. Rev. B 79, 115307 (2009)
  16. I. R. Sellers , V. R. Whiteside, I. L. Kuskovsky, A. O. Govorov and B. D. McCombe, Modulation of the Aharanov-Bohm Effect in Type-II II-VI ZnTe/ZnSe quantum dots by a Far-Infrared laser,  Physica E, 40, 1819-1823 (2008)
  17. I. R. Sellers, V. R. Whiteside, I. L. Kuskovsky, A. O. Govorov, B. D. McCombe, Aharanov-Bohm excitons at elevated temperatures in type-II ZnTe/ZnSe quantum dots, Phys. Rev. Lett. 100, 136405 (2008)
  18. M. C-K. Cheung, A. N. Cartwright, I. R. Sellers, B. D. McCombe, and I. L. Kuskovsky, Time-resolved photoluminescence of type-II quantum dots and isoelectronic centers in Zn-Se-Te superlattice structures, Appl. Phys. Lett. 92, 032106 (2008)
  19. Y. Gong, W. MacDonald, G. F. Neumark, M. C. Tamargo, and I. L. Kuskovsky, Optical Properties and Growth Mechanism of Multiple Type-II ZnTe/ZnSe Quantum Dots Grown by Migration Enhanced Epitaxy, Phys. Rev. B. 77, 155314 (2008)
  20. L. G. Mourokh, I. L. Kuskovsky, A. Yu. Smirnov, H. Matsui, Förster transfer in coupled colloidal type-II and type-I quantum dots, Proceedings of NSTI-Nanotech 2008, www.nsti.org, ISBN 978-1-4200-8503-7, 1 (2008)
  21. I. L. Kuskovsky, W. MacDonald, A. O. Govorov, L. Muroukh, X., Wei, M. C. Tamargo, M. Tadic, and F. M.  Peeters, Optical Aharonov-Bohm effect in stacked type-II quantum dots, Phys Rev B 76, 035342 (2007)
  22. Y. Gong, T. Andelman, G. F. Neumark, S. O'Brien, and I. L. Kuskovsky, Origin of defect-related green emission from ZnO nanoparticles: effect of surface modification, Nanoscale Res. Lett. 2, 297 (2007)
  23. V. M. Belous, and I. L. Kuskovsky, On Differences in Photoluminescencent and Photographic Characteristics of AgBr (100) and AgBr (111) Microcrystals I: Unsensitized and Reduction Sensitized Emulsions, J. Imaging Sci. Technol. 51, 530 - 539 (2007).
  24. I. L. Kuskovsky, Y. Gu, Y. Gong, H. F. Yan, J. Lau, I. C. Noyan, G. F. Neumark, O. Maksimov, X. Zhou, M. C. Tamargo, V. Volkov, Y. Zhu, and L. Wang, Mechanism for increasing dopant incorporation in semiconductors via doped nanostructures, Phys. Rev. B 73, 195306 (2006)
  25. Y. Gong, Hanfei F. Yan, I. L. Kuskovsky, Y. Gu, I. C. Noyan, and G. F. Neumark, and M. C. Tamargo, Structure of Zn–Se–Te system with submonolayer insertion of ZnTe grown by migration enhanced epitaxy, J. Appl. Phys. 99, 064913 (2006)
  26. O. Maksimov, Y. Gong, H. Duc, P. Fisher, M. Skowronski, I. L. Kuskovsky, and V.D. Heydemann, Structural and optical properties of GaN films grown on GaAs substrates by molecular beam epitaxy, Vacuum 80, 1042 (2006)
  27. Tamar Andelman, Yinyan Gong, Mark Polking, Ming Yin, Igor Kuskovsky, Gertrude Neumark, and Stephen O’Brien, Morphological Control and Photoluminescence of Zinc Oxide Nanocrystals, J. Phys. Chem B 109, 14314 (2005)
  28. Y. Gu, Igor L. Kuskovsky, M. van der Voort, G.F. Neumark, X. Zhou, and M.C. Tamargo, Zn-Se-Te Multilayers With Sub-monolayer Quantities of Te: Type-II Quantum Structures and Isoelectronic Centers , Phys. Rev. B 70, 045340 (2005).
  29. Y. Gu, Igor L. Kuskovsky, R. D. Robinson, I. P. Herman, G. F. Neumark, X. Zhou, S. P. Guo, M. Munoz, and M. C. Tamargo, A comparison between optically active CdZnSe/ZnSe and CdZnSe/ZnBeSe self-assembled quantum dots: effect of beryllium, Solid Sate Commun. 134, 677 (2005).
  30. Y. Gu, Igor L. Kuskovsky, Y. Min, S. O'Brien, G. F. Neumark, Quantum Confinement in ZnO Nanorods, Appl. Phys. Lett. 85, 3383 (2004).
  31. Ming Yin, Yi Gu, Igor L. Kuskovsky, Tamar Andelman, Yimei Zhu, G.F. Neumark, and Stephen O’Brien , Zinc Oxide Quantum Rods, J. Am. Chem Soc. (Communications) 126, 6206 (2004).
  32. Igor L. Kuskovsky, Y. Gu, M. van der Voort, G. F. Neumark, X. Zhou, M. Munoz, and M.C. Tamargo, Quantum structures in Zn-Se-Te system containing submonolayer quantities of Te, Phys. Stat. Sol. (b) 241 , 527 (2004).
  33. Igor L. Kuskovsky, Y. Gu, G.F. Neumark, S.P. Guo, and M.C. Tamargo, Optical properties of semiconductors with the Coulomb potential fluctuation: case of co-doped ZnSe:(N,Cl), Phys. Stat. Sol. (c) 1 , 686 (2004).
  34. Y. Gu, Igor L Kuskovsky, J. Fung, G.F. Neumark, X. Zhou, S.P. Guo, and M.C. Tamargo, Optical investigation of CdSe/Zn(Be)Se quantum dot structures: size and Cd composition, Phys. Stat. Sol. (c) 1 , 779 (2004).
  35. Y. Gu, Igor L. Kuskovsky, M. van der Voort, G. F. Neumark, X. Zhou, M. Munoz, and M. C. Tamargo, Time resolved photoluminescence studies of Zn-Se-Te nano- structures with sub-monolayer quantities of Te grown by molecular beam epitaxy, Phys. Stat. Sol. (b) 241, 550 (2004).
  36. V.N. Bondarev, Igor L Kuskovsky, Y. Gu, P.V. Pikhitsa, V. M. Belous, G.F. Neumark, S.P. Guo, and M.C. Tarmargo, “Fluctuation Theory of Donor-Acceptor Pair Luminescence in Heavily-doped Semiconductors”, Phys. Stat. Sol. (c) 1, 722 (2004).
  37. Y. Gu, I. L. Kuskovsky, J. Fung, R. Robinson, I. P. Herman, G. F. Neumark, X. Zhou, S. P. Guo, and M. C. Tamargo, CdSe/Zn(Be)Se Quantum Dot structures: Size, Chemical Composition, and Phonons, Mater. Res. Soc. Symp. Proc., 799, Z9.7.1 (2004).
  38. Y. Gong, Y. Gu, I. L. Kuskovsky, G. F. Neumark, J. Li, J. Y. Lin, H. X. Jiang and I. Ferguson, Non-equilibrium Acceptor Concentration in GaN:Mg Grown by Metalorganic Chemical Vapor Depositioin, Mater. Res. Soc. Symp. Proc., 798, Y5.16 (2004).
  39. Y. Gu, Igor L. Kuskovsky, J. Fung, R. Robinson, I.P. Herman, G.F. Neumark, X. Zhou, S.P. Guo and M.C. Tamargo, Determination of Size and Composition of Optically Active CdZnSe/ZnBeSe Quantum Dots, Appl. Phys. Lett. 83 , 3779 (2003).
  40. X. Zhou, Y. Gu, Igor L. Kuskovsky, L. Zeng, G.F. Neumark, and M.C. Tamargo, Photoluminescence of ZnxCdyMg1-x-ySe alloys as a manifestation of the breakdown of “common-anion rule”, J. Appl. Phys. 94, 7136 (2003).
  41. Y. Gu, Igor L. Kuskovsky, G. F. Neumark, X. C. Zhou, O. Maksimov, S.P. Guo, and M. C. Tamargo, Observation of Free-to-Acceptor-Type Photoluminescence in Chlorine-doped Zn(Be)Se, J. Lum. 108 , 77 (2003).
  42. Y. Gu, Igor L. Kuskovsky, G.F. Neumark, W. Lin, S.P. Guo, O. Maksimov, and M.C. Tamargo, Heavily p-type doped ZnSe using Te and N co-doping, J. Elect. Materials 31 , 799 (2002).
  43. Igor L. Kuskovsky, Y. Gu, M. van der Voort, C. Tian, B. Kim, I.P. Herman, G.F. Neumark, S. P. Guo, O. Maksimov, and M.C. Tamargo, Properties of MBE-Grown ZnBeSe: Study of Be Isoelectronic Traps and of Dopant Behavior, Phis. Stat. Sol. (b) 229 , 239 (2002).
  44. Igor L. Kuskovsky, M. van der Voort, C. Tian, G.F. Neumark, W.-C. Lin, S. P. Guo, M.C. Tamargo, A.N. Alyoshin, and V.M. Belous, Heavily p-type doped ZnSe and ZnBeSe, Phis. Stat. Sol. (b) 229 , 385 (2002).
  45. Igor L. Kuskovsky, C. Tian, C. Sudbrack, G.F. Neumark, W.-C. Lin, S. P. Guo, and M.C. Tamargo, Photoluminescence of δ-doped ZnSe:(Te,N) Grown by Molecular Beam Epitaxy, J. Appl. Phys. 90 , 2269 (2001).
  46. S. P. Guo, X. Zhou, O. Maksimov, M. C. Tamargo, C. Chi, A. Couzis, and C. Maldarelli, Igor L. Kuskovsky, and G. F. Neumark, Effects of Be on the II-VI/GaAs interface and on CdSe Quantum Dot Formation, J. Vac. Sci. Tech. B 19 , 1635 (2001).
  47. Bosang Kim, Igor L. Kuskovsky, C. Tian, Irving P. Herman, G. F. Neumark, S.P. Guo, and M.C. Tamargo, Evidence of Isoelectronic Traps in MBE Grown Zn1-xBexSe: Temperature and Pressure Dependent Photoluminescence Studies, Appl. Phys. Lett. 78 , 4151 (2001).
  48. S. P. Guo, W. Lin, X. Zhou, M. C. Tamargo, C. Tian, Igor L. Kuskovsky, and G. F. Neumark, High quality and high p-type doping of ZnBeSe using modified (N+Te) δ-doping techniques, J. Appl. Phys. 90 , 1725 (2001).
  49. Igor L. Kuskovsky, C. Tian, G.F. Neumark, J.E. Spanier, and I.P. Herman, S.P. Guo, and M.C. Tamargo, Optical Properties of δ-doped ZnSe:Te Grown by Molecular Beam Epitaxy: The Role of Tellurium, Phys. Rev. B 63 , 155205 (2001).
  50. I. L. Kuskovsky, G. F. Neumark, J. G. Tischler, and B. A. Weinstein, Resonant donor defect as a cause of compensation in p-type ZnSe: Photoluminescence studies under hydrostatic pressure, Phys. Rev. B 63, 161201 (2001).
  51. I. Kuskovsky, C. Tian, C. Sudbrack, G. F. Neumark, S. P. Guo, and M. C. Tamargo, Photoluminescence Characterization of MBE Grown ZnBeSe, J. Crystal Growth 214/215 , 1058 (2000).
  52. W. Lin, S.P. Guo, M.C. Tamargo, I. Kuskovsky, C. Tian, and G. F. Neumark, Enhancement of p-type Doping of ZnSe Using a Modified (N+Te) δ-doping Technique, Appl. Phys. Lett. 76 , 2205 (2000).
  53. S. P. Guo, Y. Luo, W. Lin, O. Maksimov, M. C. Tamargo, I. Kuskovsky, C. Tian, and G. F. Neumark, High Crystalline Quality ZnBeSe Grown By Molecular Beam Epitaxy With Be-Zn Co-Irradiation, J. Crystal Growth 208 , 205 (2000).
  54. I. Kuskovsky, B. S. Lim, and A. S. Nowick, Low-temperature Dielectric Relaxation Peaks Involving Proton Tunneling in Ba1-xNdxCeO3, Phys. Rev. B 60 , R3713 (1999).
  55. I. Kuskovsky, D. Li, G.F. Neumark, V. N. Bondarev, and P. V. Pikhitsa, The Role of Potential Fluctuations in cw Luminescence of Heavily Doped Materials, Appl. Phys. Lett. 75 , 1243 (1999).
  56. B. Kim, I. Kuskovsky, I. P. Herman, D. Li, and G. F. Neumark, Reversible Ultraviolet-induced Photoluminescence Degradation and Enhancement in GaN Films, J. Appl. Phys. 86, 2034 (1999).
  57. I. Kuskovsky, G.F. Neumark, V.N. Bondarev, and P.V. Pikhitsa, Study of Luminescence in Semiconductors in the Presence of Fluctuations, Proceedings of ICPS 24, Jerusalem, Israel ed. D. Gershon, World Scientific, Singapore, 1999.
  58. A.S. Nowick, A.V. Vaysleyb, and I. Kuskovsky, Universal Dielectric Response (UDR) of Variously Doped CeO2 Ionically Conducting Ceramics, Phys. Rev. B 58, 8398 (1998).
  59. I. Kuskovsky, G.F. Neumark, V.N. Bondarev, and P.V. Pikhitsa, Decay Dynamics In Disordered Systems: Application To Heavily Doped Semiconductors, Phys. Rev. Lett. 80 , 2413 (1998).
  60. I. Kuskovsky, D. Li, G.F. Neumark, M. Moldovan, N. Giles, V.N. Bondarev, and P.V. Pikhitsa, Time-Resolved Photoluminescence of Nitrogen Doped ZnSe: Role of Fluctuations, J. Crystal Growth 184/185, 525 (1998).
  61. C. Kothandaraman, I. Kuskovsky, G.F. Neumark, and R.M. Park, Time-Resolved Luminescence Studies Of Heavily Nitrogen Doped Znse, Appl. Phys. Lett. 69, 1523 (1996).
  62. I. Kuskovsky and G. F. Neumark, Characterization of ZnSe:N using screening effects, Mater. Res. Soc. Symp. Proc., 406 , 443 (1996).
  63. I. Kuskovsky and G.F. Neumark, Doping And Non-Equilibrium During Low-Temperature Growth (Application To MBE), Inst. Phys. Conf. Ser. 155 , 227 (1996).
  64. V. N. Bondarev and I. Kuskovsky, Dynamics of Fluctuations and 'Universal' Electrical Response in Conducting Systems, Sov. Electrochem. 28 , 1254, (1992).
  65. V. N. Bondarev and I. Kuskovski, On the Theory of Roton-Limited Mobility of Charges in HeII, Sov. Journal of Low Temp. Phys. 18, 217 (1992).