Research interests and current projects:
Photovoltaics (Solar cells)
III-V on Silicon multi-junction devices
Ultra-high efficiency PV devices
Advanced characterization of PV materials and devices
MicroElectroMechanical Systems (MEMS)
Extreme MEMS (NEMS, high-Q, low temperature, quantum mechanical oscillators)
Piezoelectric MEMS (III-V semiconductors, Lithium Niobate, Quartz)
Optical MEMS (MEMS coupled to integrated optics)
Lab-on-a-Chip (optical-microfluidic integration)
Microrobotics and energy harvesting
Photovoltaics (Solar cells)
The development of viable sustainable energy resources is arguably the most pressing technological demand of our time due to the high monetary and environmental costs of fossil fuel usage. The depletion of supplies has significantly increased their cost and the concomitant burning has led to rapid and dramatic signs of climate change. The associated pollutants have had increasingly severe effects on public health. None of these problems will be solved without the development of a clean sustainable energy supply. The stability of our economies, climate and health are depending on a technical solution to this unfolding crisis.
My research program is a multi-faceted effort to develop high efficiency and low cost photovoltaic devices. Theoretical efficiencies for single junction devices are limited to ~30% at 1 sun, based upon standard assumptions for the conversion of light to electron-hole pairs in a semiconductor. A proven route to higher efficiencies is via multijunction solar cell technology in which monolithic series-connected solar cells are fabricated, with each cell optimized for a different part of the solar spectrum. Current multijunction devices are expensive relative to single junction devices due to the high cost of their exotic substrates. We are developing a new generation of multijunction solar cells, based upon the growth of III-V semiconductors on high quality ubiquitous Silicon substrates to achieve high efficiencies, providing a significantly lower cost per installed Watt. We are also developing other third generation devices, based upon novel materials, concepts and architectures.
MicroElectroMechanical Systems (MEMS) devices are miniature mechanical objects that can be fabricated using the well-established tools used to manufacture modern integrated circuits. It is now possible to make mechanical objects as small as the component transistors in an integrated circuit, now well below 1 µm (1 millionth of a meter). Ideally and very fruitfully these mechanical objects can be integrated with electronic circuitry, leading to tremendous reductions in costs and increases in yield associated with mass production.
The mechanical objects can serve as sensors or actuators in a number of research and commercial applications, allowing for replacement of conventional technology with MEMS technology. As MEMS technology is being explored, it is becoming increasingly clear that new applications and new capabilities are facilitated by MEMS technology, making it a truly disruptive technology - changing the way we think about technology and use technology. These opportunities are very exciting, because they cover such a broad range of disciplines, bridge many disciplines, and are limited only by our own creativity in implementing their use.
“Fabrication of nanoscale single crystal InP membranes”, O. V. Hulko, B. J. Robinson and R. N. Kleiman, Appl. Phys. Lett., 91, 053119 (2007).
"Drift-Free, 1000G Mechanical Shock Tolerant Single-Crystal Silicon Two-Axis MEMS Tilting Mirrors in a 1000x1000-Port Optical Crossconnect", A. Gasparyan, H. Shea, S. Arney, V. Aksyuk, M.E. Simon, F. Pardo, H.B. Chan, J. Kim, J. Gates, J. S. Kraus, S. Goyal, D. Carr and R. N. Kleiman, post deadline paper PD36-1, OFC (2003).
"Alternative Training Methodologies for Large Scale Optical Crossconnects", R. N. Kleiman, LU Proprietary Technical Memorandum, April 10, 2002.
"Origin of Drift in SOI MEMS Devices: Microscopy and Modeling", R. N. Kleiman, LU Proprietary Technical Memorandum, July 18, 2001.
"Nonlinear Mechanical Casimir Oscillator", H. B. Chan, V. A. Aksyuk, R. N. Kleiman, D. J. Bishop, and Federico Capasso, Phys. Rev. Lett., 87, 211801 (2001).
"Quantum Mechanical Actuation of Microelectromechanical Systems by the Casimir Force", H. B. Chan, V. A. Aksyuk, R. N. Kleiman, D. J. Bishop, and Federico Capasso, Science, 291, 1941 (2001).
"Scanning capacitance microscopy imaging of Silicon MOSFETs", R. N. Kleiman, M. L. O'Malley, F. H. Baumann, J. P. Garno, and G. L. Timp, J. Vac. Sci. Tech. B18, 2034 (2000).
"50-nm Vertical Replacement-Gate (VRG) pMOSFETs", Sang-Hyun Oh, J. M. Hergenrother, T. Nigam, D. Monroe, F. P. Klemens, A. Kornblit, W. M. Mansfield, M. R. Baker, D. L. Barr, F. H. Baumann, K. J. Bolan, T. Boone, N. A. Ciampa, R. A. Cirelli, D. J. Eaglesham, E. J. Ferry, A. T. Fiory, J. Frackoviak, J. P. Garno, H. J. Gossmann, J. L. Grazul, M. L. Green, S. J. Hillenius, R. W. Johnson, R. C. Keller, C. A. King, R. N. Kleiman, J. T-C. Lee, J. F. Miner, M. D. Morris, C. S. Rafferty, J. M. Rosamilia, K. Short, T. W. Sorsch, A. G. Timko, G. R. Weber, G. D. Wilk, and J. D. Plummer, IEDM Tech. Dig., pp. 65-68, (2000).
"Metal-insulator-semiconductor tunneling microscope: two-dimensional dopant profiling of semiconductors with conducting atomic-force microscopy", S. Richter, M. Geva, J. P. Garno and R. N. Kleiman, Applied Physics Letters, 77, 456 (2000).
"Imaging of Acoustic Fields in Bulk Acoustic Wave Thin-Film Resonators", H. F. Safar, R. N. Kleiman, B. P. Barber, P. L. Gammel, J. Pastalan, H. A. Huggins, L. A. Fetter, and R. E. Miller, Applied Physics Letters, 77, 136 (2000).
"The Ballistic Nano-transistor", G. Timp, J. Bude, K. K. Bourdelle, J. Garno, M. Green, H. Gossmann, G. Forsyth, Y. Kim, R. Kleiman, A. Kornblit, F. Klemens, C. Lochstampfor, W. Mansfield, S. Moccio, T. Sorch, W. Timp, D. M. Tennant, and R. T. Tung, IEDM Tech. Dig., pp. 55-58, (1999).
"The Vertical Replacement-Gate (VRG) MOSFET: A 50 nm Vertical MOSFET with Lithography-Independent Gate Length", J. M. Hergenrother, D. P. Monroe, M. Baker, F. Baumann, K. J. Bolan, J. E. Bower, N. A. Ciampa, R. Cirelli, D. J. Eaglesham, J. Frackoviak, S. J. Hillenius, C. A. King, R. Kleiman, F. P. Klemens, A. Kornblit, W. Y.-C. Lai, J. T.-C. Lee, R. C. Liu, W. M. Mansfield, M. D. Morris, C.-S. Pai, T. W. Sorsch, H.-H. Vuong, G. R. Weber, J. M. Rosamilia, H. J. Gossmann, C. S. Rafferty, J. Colonell, H. Maynard, and M. L. Green, IEDM Tech. Dig., pp. 75-78, (1999).
"Electrical Simulation of Scanning Capacitance Microscopy Imaging of the PN Junction with Semiconductor Probe Tips", M. L. O'Malley, G. L. Timp, W. Timp, S. V. Moccio, J. P. Garno, and R. N. Kleiman, Applied Physics Letters, 74, 3672 (1999).
"Transparent Electrodes for Electro-optic Modulators", R. N. Kleiman, R. Fleming, D. Gill, J. R. Kwo, J. Osenbach, and G. A. Thomas, Lucent Proprietary Technical Memorandum, September 13, 1999.
"Quantification of Scanning Capacitance Microscopy Imaging of the PN Junction Through Electrical Simulation", M. L. O'Malley, G. L. Timp, S. V. Moccio, J. P. Garno, and R. N. Kleiman, Applied Physics Letters, 74, 272 (1999).
"Ultra-thin Gate Oxides and Ultra-shallow Junctions for High Performance, sub-100nm pMOSFETs", G. Timp, A. Agarwal, K. K. Bourdelle, J. E. Bower, T. Boone, J. Garno, A. Ghetti, M. Green, H. Gossmann, D. Jacobson, R. Kleiman, A. Kornblit, F. Klemens, S. Moccio, M. L. O'Malley, L. Ocola, J. Rosamilia, J. Sapjeta, P. Silverman, T. Sorsch, W. Timp, and D. Tennant, IEDM Tech. Dig., pp. 1041-1043, (1998).
"Two-Dimensional Dopant Profiling of a 60nm Gate Length nMOSFET using Scanning Capacitance Microscopy", W. Timp, M. O'Malley, R. N. Kleiman, and J. P. Garno, IEDM Tech. Dig., pp. 555-558, (1998).
"Progress toward 10 nm CMOS Devices", G. Timp, F. H. Baumann, T. Boone, R. Cirelli, J. Garno, A. Ghetti, M. Green, H. Gossmann, R. Kleiman, A. Kornblit, F. Klemens, W. Mansfield, S. Moccio, D. A. Muller, M. O'Malley, L. E. Ocola, J. Rosamilia, J. Sapjeta, P. Silverman, T. Sorsch, W. Timp, D. Tennant, and B. E. Weir, IEDM Tech. Dig., pp. 615-618, (1998).
"Direct Channel Length Determination of sub-100nm MOS Devices Using Scanning Capacitance Microscopy", R. N. Kleiman, M. L. O'Malley, F. H. Baumann, J. P. Garno, W. G. Timp, and G. L. Timp, Symp. on VLSI Tech. Dig., pp. 138-139, (1997).
"Low Leakage 1.5nm Ultra-thin gate oxides for Extremely High Performance sub-100nm n-MOSFETs", G. Timp, A. Agarwal, F. H. Baumann, M. Buonanno, R. Cirelli, V. Donnelly, M. Foad, D. Grant, M. Green, H. Gossmann, S. Hillenius, J. Jackson, D. Jacobson, R. Kleiman, A. Kornblit, F. Klemens, J. T-C Lee, W. Mansfield, S. Moccio, A. Murrell, M. O'Malley, J. Rosamilia, J. Sapjeta, P. Silverman, T. Sorsch, W. W. Tai, D. Tennant, H. Vuong, B. Weir, IEDM Tech. Dig., pp. 930-932, (1997).
"Junction Delineation of 0.15?m MOS Devices Using Scanning Capacitance Microscopy", R. N. Kleiman, M. L. O'Malley, F. H. Baumann, J. P. Garno, and G. L. Timp, IEDM Tech. Dig., pp. 691-694, (1997).
R. N. Kleiman, "Method and Geometry for Reducing Drift in Electrostatically Actuated Devices", Patent 6,888,658 granted May 5, 2005 by the U. S. Patent and Trademark Office.
R. N. Kleiman, R. M. Fleming, J. R. Kwo, J. W. Osenbach, G. A. Thomas, "Improved Electro-Optic Device Including a Buffer Layer of Transparent Conductive Material", US Patent 6,480,633 granted November 12, 2002.
R. N. Kleiman, M. L. O'Malley, and G. L. Timp, "Scanning Depletion Microscopy for Carrier Profiling", US Patent 6,417,673 granted July 9, 2002.
B. Barber, P. Gammel, R. N. Kleiman, H. Safar, "Scanning RF Mode Microscope", US Patent 6,305,226 granted October 23, 2001.
R. N. Kleiman, "Micropositioning Devices Using Single-Crystal Piezoelectric Materials", US Patent 5,739,624 granted April 14, 1998.