Dr. Sasangan Ramanathan, Dean- Engineering and a Professor in the Department of Chemical Engineering and Materials Science, brings with him over 20 years of international research, management and leadership experience. Dr. Sasangan’s focus and dedication is in preparing the next generation graduates for challenges in science, engineering, technology and management. He represents the university’s commitment to excellence in teaching, learning, research and positive contribution to the society. He is a strong believer in an educational process that promotes creativity, innovation and entrepreneurship while providing the students with strong fundamentals. Dr. Sasangan Ramanathan holds a Ph. D. in Chemical Engineering from Clarkson University (USA), has served in various capacities in research and development in the US. Recently, he served as the Chief Technology Officer for a multi-million dollar company in the US in developing cutting edge technology for advanced semiconductor device fabrication.

He is well recognized by leading semiconductor device manufacturers like Samsung, SK Hynix, Fujitsu and Toshiba (to name a few). He has been an active member in defining the semiconductor technology roadmap, driving new product development,Besides an illustrious career in the semiconductor industry, Dr. Sasangan was also involved in developing novel catalytic materials aimed at reducing the emission of ozone depleting toxic gases. Besides being an active researcher, he joins Amrita with strong leadership skills and management experience.leading strategic business development,managing alliances/collaborations with key industry partners/consortia & universities across the globe. Dr. Sasangan has a strong passion for innovation and creativity.

Besides an illustrious career in the semiconductor industry, Dr. Sasangan  was also involved in developing novel catalytic materials aimed at reducing the emission of ozone depleting toxic gases. Besides being an active researcher, he joins amrita with strong leadership skills and management experience.

He has authored/co-authored over 45 publications in international journals  and conferences and holds 12 patents. He also served on the International Technical Advisory committee in the American Vacuum Society’s topical conference on Atomic Layer Deposition. He is also an active participant and member of the advisory committee of topical conferences in Electrochemical Society and American Chemical Society and has chaired a number of international conference sessions.


1995 PhD in Chemical Engineering Clarkson University, Potsdam, NY 13676 USA
1991 Postgraduate Degree Clarkson University, Potsdam, NY 136786 USA
1989 Undergraduate Degree National Institute of Technology, Trichy, India


Year Affiliation
April 2014 – Present Dean Engineering, Amrita School of Engineering
Professor Department of Chemical Engineering and Materials Science, Amrita University
Apr 2001 – Feb 2014 AIXTRON, Inc., Sunnyvale, CA USA  
Apr 2008 – Feb 2014 Chief Technology Officer
Jan 2004 – Mar 2008 Vice President, Technology
Apr 2001- Dec 2003 Director, Technology


  • Deposition and characterization of materials for advanced CMOS process technology (14nm and beyond)
  • Surface Science and Catalysis
  • Advanced deposition technologies such as Atomic Layer Deposition to “tailor the material properties” for various applications

Sponsored Projects (Submitted)

Investigation on High Performance Nano Adhesive Bonding of Ultra High Temperature Resistant Polymer and its Performance under Space Environments


Publication Type: Patent
Year of Publication Publication Type Title
2015 Patent W. PARK, Jang, Y. J., Kim, G. Y., Lu, B., Siu, G., Silva, H., and Ramanathan S., “Method for forming TiSiN thin film layer by using atomic layer deposition”, U.S. Patent US 14/391,2942015.[Abstract]

There is disclosed a method for forming a TiSiN thin film on a substrate according to ALD including a first process of preheating a substrate while supplying Ar or N2 containing inert gas to a chamber, after disposing a substrate in a chamber; a second process of forming a TiN film on the substrate by repeating at least one time a process of purging over-supplied Ti containing gas after supplying Ti containing gas and inert gas after that and a process of purging residual product after supplying N containing gas and inert gas after that; a third process of forming a SiN film by repeating at least one time a process of purging over-supplied Si containing gas after supplying Si containing gas on the TiN film and supplying inert gas after that and a process of purging residual product after supplying N containing gas and supplying inert gas after that; and a fourth process of forming a TiSiN film having a desired thickness by repeating the second and third processes at least one time, a partial pressure range of the gas used in forming the TiSiN thin film is Ti containing gas: 9×10−3 Torr or less, Si containing gas: 1×10−3˜3×10−1 Torr and N containing gas: 7×10−3˜6×10−1 Torr, and a pressure range of the gas is 500 mTorr˜5 Torr and the Si content of the formed TiSiN thin film is 20 atom % or less.

More »»
2011 Patent Kim G. Y., Srivastava A., Seidel T. E., Londergan A. R., and Ramanathan S., “Transient Enhanced Atomic layer Deposition”, U.S. Patent 79814732011.
2006 Patent J. Puchacz, Ramanathan S., Reyes, M., and Seidel, T., “Multi-single Wafer Processing Apparatus”, U.S. Patent US 11/224,7672006.[Abstract]

A wafer processing apparatus includes one or more processing modules, each having multiple, distinct, single-wafer processing reactors configured for semi-independent ALD and/or CVD film deposition therein; a robotic central wafer handler configured to provide wafers to and accept wafers from each of said wafer processing modules; and a single-wafer loading and unloading mechanism that includes a loading and unloading port and a mini-environment coupling the loading and unloading port to the robotic central wafer handler. The wafer processing reactors may be arranged (i) along axes of a Cartesian coordinate system, or (ii) in quadrants defined by said axes, one axis being parallel to a wafer input plane of the at least one of the process modules to which the single-wafer processing reactors belong. Each processing module can include up to four single-wafer processing reactors, each with an independent gas distribution module. More »»
2005 Patent S. H. Lee and Ramanathan S., “Method for the Formation of Diffusion Barrier”, U.S. Patent US 10/425,3062005.[Abstract]

Electronic components such as semiconductor wafer VLSI and ULSI integrated circuit devices are provided having a robust barrier layer in the device interconnects. The robust barrier layer provides excellent step coverage, low resistance and enhanced adhesion to CVD copper and the interconnect has a double structure of a layer of a barrier material and a metal layer thereon. The metal layer is preferably tungsten and is formed by replacing silicon or other such atoms on the surface of the barrier layer with tungsten metal. A layer of silicon can be formed on the barrier layer, silicon atoms can be formed on the surface by reacting the barrier layer with a silicon containing reactant or a silicon containing barrier layer can be used. More »»
2005 Patent S. Gopinath, Van Cleemput, P. A., Schulberg, M., Ramanathan S., Juarez, F., and Joyce, P., “Method and Apparatus for Introduction of Solid Precursors and Reactants into a Supercritical Fluid Reactor”, U.S. Patent US 10/016,0172005.[Abstract]

The present invention pertains to apparatus and methods for introduction of solid precursors and reactants into a supercritical fluid reactor. Solids are dissolved in supercritical fluid solvents in generator apparatus separate from the supercritical fluid reactor. Such apparatus preferably generate saturated solutions of solid precursors via recirculation of supercritical fluids through a vessel containing the solid precursors. Supercritical solutions of the solids are introduced into the reactor, which itself is charged with a supercritical fluid. Supercritical conditions are maintained during the delivery of the dissolved precursor to the reactor. Recirculation of supercritical precursor solutions through the reactor may or may not be implemented in methods of the invention. Methods of the invention are particularly well suited for integrated circuit fabrication, where films are deposited on wafers under supercritical conditions. More »»
2005 Patent X. Liu, Seidel, T., Lee, E., Doering, K., and Ramanathan S., “Methods and Apparatus for Cycle Time Improvements for Atomic Layer Deposition”, 2005.[Abstract]

Different periods of an ALD cycle are performed using different purge flows and, in some cases, different pumping capacities, while maintaining the reactor chamber at a nominally constant pressure. The purge flows may, in some cases, utilize different gasses and/or may be provided through different flow paths. These operations provide for ALD cycle time improvements and economical operation with respect to consumables usage. In some embodiments the use of an annular throttle valve provides a means for controlling downstream flow limiting conductances in a gas flow path from the reactor chamber. More »»
2004 Patent A. R. Londergan, Ramanathan S., Winkler, J., and Seidel, T. E., “Passivation Method for Improved Uniformity and Repeatability for Atomic Layer Deposition and Chemical Vapor Deposition”, U.S. Patent US 10/262,9922004.[Abstract]

A method to deposit a passivating layer of a first material on an interior reactor surface of a cold or warm wall reactor, in which the first material is non-reactive with one or more precursor used to form a second materials. Subsequently when a film layer is deposited on a substrate by subjecting the substrate to the one or more precursors, in which at least one precursor has a low vapor pressure, uniformity and repeatability is improved by the passivation layer. More »»
2003 Patent J. Dalton, Powell, R. A., Kailasam, S. K., and Ramanathan S., “Forming Metal-derived Layers by Simultaneous Deposition and Evaporation of Metal”, U.S. Patent US 09/975,6122003.[Abstract]

The present invention pertains to methods for forming metal-derived layers on substrates. Preferred methods apply to integrated circuit fabrication. In particular, selective methods may be used to form diffusion barriers on partially fabricated integrated circuits. In one preferred method, a wafer is heated and exposed to a metal vapor. Under specific conditions, the metal vapor reacts with dielectric surfaces to form a diffusion barrier, but does not react with metal surfaces. Thus, methods of the invention form diffusion barriers that selectively protect dielectric surfaces but leave metal surfaces free of diffusion barrier. More »»
2000 Patent Ramanathan S., A., K., and A., F. G., “Surface Modification of Semiconductors using Electromagnetic Radiation”, U.S. Patent 60157592000.
1999 Patent Ramanathan S., B., D. S., and C.A., S., “Flash Evaporator”, 1999.
Publication Type: Conference Proceedings
Year of Publication Publication Type Title
2013 Conference Proceedings Ramanathan S., “Atomic Layer Deposition of Materials for Alternate Non-Volatile Memory Technologies”, Invited Talk at the 13th Atomic Layer Deposition Conference, American Vacuum Society. 2013.
2012 Conference Proceedings L. Yang, Weber, U., Maumann, P. K., Karim, Z., Ramanathan S., Lu, B., Czubatyj, W., Hudgens, S., and Lowrey, T., “Deposition and Electrical Characterization of ALD GexSbyTez for Future Applications”, 12th International Conference on Atomic Layer Deposition, American Vacuum Society. 2012.
2011 Conference Proceedings B. Lu, Karim, Z., and Ramanathan S., “Material and Tool Design Challenges for Taking ALD to High Volume Production Beyond 30nm Node”, Symposium on Manufacturing and Technology Section MS2, American Vacuum Society. 2011.
2011 Conference Proceedings L. Yang, Weber, U., Baumann, P. K., Mack, J., Karim, Z., Ramanathan S., and Lu, B., “Atomic Layer Deposition of Smooth Phase Change GexSbyTez Layers on Planar and 3D Structures”, International Conference on Atomic Layer Deposition, American Vacuum Society. 2011.
2010 Conference Proceedings P. Lehnen, Weber, U., Baumann, P. K., Senzaki, Y., Karim, Z., Ramanathan S., Lu, B., Reed, J., Czubatyj, W., Hudgens, S., and Dennison, C., “Void Free Gapfill and Phase Change Memory Device Characterization of GeSbTe Films Deposited Using Atomic Vapor Deposition”, 10th Atomic Layer Deposition Conference, American Vacuum Society. 2010.
2009 Conference Proceedings Z. Karim, Senzaki, Y., . Y Kim, G., Barelli, C., Okuyama, Y., Kim, H. Y., Lu, B., Lindner, J., and Ramanathan S., “Needs for Next Generation Memory and Enabling Solutions based on Advanced Vaporizer Technology”, 9th Atomic Layer Deposition Conference, American Vacuum Society. 2009.
2009 Conference Proceedings Ramanathan S., “Development of Next Generation High-k Filmss – Challenges and Solutions”, European Materials Research Society Spring Meeting. France, 2009.
2009 Conference Proceedings C. Barelli, . Y Kim, H., . Y Kim, G., Senzaki, Y., Okuyama, Y., Mack, J., Lindner, J., Lu, B., Karim, Z., and Ramanathan S., “Highly Conformal ALD of LaOx and La-based High-k Dielectric Films Using Novel Vaporizer Technology”, Materials Research Society Spring Meeting. 2009.
2008 Conference Proceedings C. Choi, Ando, T., Karim, Z., and Ramanathan S., “Modulating Work Function for pFET with AVD Ru-based and TaN-based Gate Electrodes”, 39th IEEE Semiconductor Interface Specialist Conference. 2008.
2005 Conference Proceedings H. J. Lim, Kim, Y. S., Jung, H. S., Han, S. K., Kim, M. J., Lee, J. H., Lee, N. I., Chung, Y., Kim, H. Y., Lee, N. K., Ramanathan S., Seidel, T. E., and Boleslawski, M., “Evaluation od ALD Hafnium Silicate and Improvement of Reliability Characteristics”, Atomic Layer Deposition Conference. 2005.
2004 Conference Proceedings Kim G. Y., Srivastava A., D., F., A., L., Z., K., Seidel T. E., and Ramanathan S., “A High Deposition Rate Process Using Limited Optimized Reaction ALD”, Atomic Layer Deposition Conference”, Atomic Layer Deposition Conference, American Vacuum Society. pp. 1308-1311, 2004.
2004 Conference Proceedings X. Liu, Ramanathan S., Lee, E., and Seidel, T. E., “Atomic Layer Deposition of Aluminum Nitride Thin Films from Trimethyl Aluminum (TMA) and Ammonia”, MRS Proceedings. Cambridge Univ Press, pp. 11-18, 2004.[Abstract]

luminum nitride (AlN) thin films were deposited from trimethyl aluminum (TMA) and Ammonia (NH3) by thermal atomic layer deposition (thermal ALD) and plasma enhanced atomic layer deposition (PEALD) on 200 mm silicon wafers. For both thermal ALD and PEALD, the deposition rate increased significantly with the deposition temperature. The deposition rate did not fully saturate even with 10 seconds of NH3 pulse time. Plasma significantly increased the deposition rate of AlN films. A large number of incubation cycles were needed to deposit AlN films on Si wafers. 100% step coverage was achieved on trenches with aspect ratio of 35:1 at 100 nm feature size by thermal ALD. X-ray diffraction (XRD) data showed that the AlN films deposited from 370 °C to 470 °C were polycrystalline. Glancing angle X-ray reflection (XRR) results showed that the RMS roughness of the films increased as the film thickness increased. More »»
2003 Conference Proceedings A. R. Londergan, Ramanathan S., Winkler, J., Seidel, T. E., Gutt, J., Brown, G., and Murto, R. W., “PATHWAYS FOR ADVANCED TRANSISTORS USING HAFNIUM–BASED OXIDES BY ATOMIC LAYER DEPOSITION”, Electrochemical Society. pp. 243-264, 2003.
2003 Conference Proceedings X. Liu, Ramanathan S., and Seidel, T. E., “Atomic layer deposition of hafnium oxide thin films from tetrakis (dimethylamino) hafnium (TDMAH) and ozone”, MRS Proceedings. Cambridge Univ Press, pp. 97-102, 2003.[Abstract]

Hafnium oxide (HfO2) thin films were synthesized from tetrakis(dimethylamino) hafnium (TDMAH) and ozone (O3) by atomic layer deposition (ALD) on 200 mm silicon wafers. Gradual saturation was observed for TDMAH exposure pulse. However O3 showed better saturation behavior for O3exposure. Yet, 100% step coverage was achieved for ~100nm trenches with aspect ratio of 35. Temperature dependence of the deposition rate was studied at susceptor temperature from 160°C to 420°C. The lowest deposition rate was observed at 320°C. Mercury probe measurements indicated the dielectric constant increased from 16 to 20 as susceptor temperature increased from 200°C to 320°C. Selected comparisons with tetrakis (ethylmethylamino) hafnium (TEMAH) were also made. More »»
2002 Conference Proceedings J. H. Lee, J., K., S., K. Y., S., J. H., Lee, N. I., Kang, H. K., Suh, K. P., Jeong, M. M., Hyun, K., Baik, H. S., Chung, Y. S., Liu, X., Ramanathan S., Seidel, T. E., Winkler, J., Londergan, A., Kim, H. Y., M., J., and Lee, N. K., “Mass Production Worthy HfO2-Al2O3 Laminates Capacitor Technology using Hf Liquid Precursor for sub-100 nm DRAMS”, Techincal Digest, International Electron Devices Meeting. pp. 221-224, 2002.
Publication Type: Conference Paper
Year of Publication Publication Type Title
2012 Conference Paper Z. Karim, Yang, L., Mack, J., Liu, M., Weber, U., Baumann, P., Ramanathan S., Lu, B., Czubatyj, W., Hudgens, S., and , “Advances in ALD GST Process and Equipment for sub-20nm PCRAM Devices: Precursor delivery, GST Gapfill and Electrical Characterization”, in Conference Proceedings by the Society for Solid State and Electrochemical Science and Technology, 2012.
2008 Conference Paper Y. Senzaki, Seidel, T., McCormick, J., Kim, G. Y., Kim, H. Y., Karim, Z., Lu, B., Ramanathan S., Lindner, J., Silva, H., and Daulesberg, M., “Atomic Level Solutions for Advanced Microelectronic Applications”, in International Conference on Solid State and Integrated Circuit Technology, ICSICT 2008. , 2008.[Abstract]

Atomic Layer Deposition (ALD) has successfully been applied to advanced microelectronic applications importantly for conformal coatings on high aspect ratio devices. However, traditional ALD is limited in deposition rate because the ability to bring precursors rapidly to the surface. In this paper we review recent results for precursor delivery using advanced vaporization (Trijet) as well as recent advances in Pulsed CVD (AVD®) using art elements held in common with ALD technology. These and other advances - such as Multiple Single Wafer configurations allow ALD application for continued scaling under conditions of improved process control and higher productivity. Key applications include: capacitors (dielectrics and electrodes), transistors and contacts. This paper reviews these technological advances in the context of their applications. More »»
Publication Type: Journal Article
Year of Publication Publication Type Title
2009 Journal Article Y. Senzaki, Okuyama, Y., Kim, G., Kim, H. Young, Barelli, C., Lindner, J., Karim, Z., and Ramanathan S., “Highly Conformal ALD of ZrO2 at Higher Process Temperatures than the Conventinal TEMAZr-Based Process”, ECS Transactions, vol. 25, pp. 201–209, 2009.[Abstract]

An alternative Zr source to tetrakis(ethylmethylamino)zirconium (TEMAZr) was evaluated in this study to develop more thermally robust 300mm ZrO2 ALD process. It was observed that a transition from ALD to CVD takes place at approximately 340åC susceptor temperature. This temperature is significantly higher than that for the commonly used TEMAZr-based ALD process by approximately 40åC. Excellent step coverage of near 100% of ALD ZrO2 has been achieved in 40:1 aspect ratio structures using this new ZrO2 ALD process. ZrO2 ALD films of 5.5nm thickness demonstrated a low leakage current of 2x10-9A/cm2 at 1.2V. More »»
2008 Journal Article Z. Karim, Senzaki, Y., Ramanathan S., Lindner, J., Silva, H., and Dauelsberg, M., “Advances in ALD Equipment for sub-40nm Memory Capacitor Dielectrics: Precursor delivery, Materials and Processes”, ECS Transactions, vol. 16, pp. 125–134, 2008.[Abstract]

In DRAM, maintaining the cell capacitance more than 25 fF/cell with shrinking cell capacitance area has been accomplished with the introduction of higher k oxides as the capacitor dielectric. Higher k materials include Al2O3, HfO2, ZrO2 or a combination of HfO2/Al2O3/HfO2 and ZrO2/Al2O3/ZrO2. These materials can satisfy DRAM device requirements down to the 50 nm node. However, for sub 40nm DRAM technology nodes, precursor delivery challenges are far greater and require unique precursor delivery methodology to ensure >90% conformality in high aspect ratio DRAM capacitor structures, while maintaining higher productivity. The precursor delivery problem is due to the very low vapor pressures of the precursors for advanced high k dielectrics.. This paper highlights the progress made in ALD equipment development offering solutions for critical problems facing sub 40nm DRAM technology nodes. Particularly, this paper describes a unique pulsed vaporization technology (TriJet®) coupled with a high performance ALD reactor that offers solution for next generation high k film deposition without compromising productivity. More »»
2007 Journal Article J. Dalton, Kim, H. Young, Zhang, Z., Seidel, T., Karim, Z., and Ramanathan S., “High Performance ALD Reactor for High-k Films”, ECS Transactions, vol. 3, pp. 27–36, 2007.[Abstract]

In this work we discuss the design requirements for achieving higher productivity ALD solutions and we present a single-wafer reactor design that incorporates improvement elements. The effectiveness of this approach is evaluated by examining the improved step coverage, saturation, uniformity and electrical properties of ZrO2 high-k films deposited using this reactor system. More »»
2006 Journal Article Z. Karim, Biossiere, O., Lohe, C., Zhang, Z., Park, W., Manke, C., Baumann, P. K., Dalton, J., Ramanathan S., Lindner, J., and , “Advanced Metal Gate Electrode Options Compatible with ALD and AVD® HfSiOx-based Gate Dielectrics”, ECS Transactions, vol. 3, pp. 363–374, 2006.[Abstract]

We have investigated metal gate electrodes for use with high k HfSiOx gate dielectric films using AVD® and ALD technology. First, we report on the characterization of the AVD® and ALD deposition techniques where both HfO2 and SiO2 are combined for the formation of HfSiOx. Nitrogen is then incorporated using both in-situ and ex-situ methods to form HfSiON and the resulting film properties are compared. Using an AVD process a work-function of >4.7eV for Ru and RuO2 gate electrode metals in combination with HfSiOx was obtained. A TaN-based metal gate was also characterized to target a promising pMOS solution using different compositions. Together with its high flexibility and composition control, both ALD and AVD® can become key processes for advanced high-k dielectrics as well as compatible CMOS metal electrodes. More »»
2005 Journal Article X. Liu, Ramanathan S., Longdergan, A., Srivastava, A., Lee, E., Seidel, T. E., Barton, J. T., Pang, D., and Gordon, R. G., “ALD of Hafnium Oxide Thin Films from Tetrakis (ethylmethylamino) Hafnium and Ozone”, Journal of The Electrochemical Society, vol. 152, pp. G213–G219, 2005.[Abstract]

Hafnium oxide (HfO2)(HfO2) thin films were deposited from tetrakis(ethylmethylamino)hafnium (TEMAH) and ozone (O3)(O3) by atomic layer deposition (ALD) on 200 mm silicon wafers. The O3O3 half-reaction shows good saturation behavior. However, gradual surface saturation is observed for the TEMAH half-reaction. Within wafer non-uniformity of less than 1% and step coverage of about 100% were achieved for trenches with aspect ratio of around 40:1. The film thickness increased linearly as the number of cycles increased. From susceptor temperatures of 160-420°C, the lowest deposition rate (Å/cycle) and the highest refractive index is observed at 320°C. The atomic ratio of hafnium to oxygen determined by Rutherford backscattering is 1:2.04 for the films deposited at 320°C. The carbon and hydrogen content determined by secondary ion mass spectroscopy (SIMS) decreased as the susceptor temperature increased from 200 to 320°C. Lower carbon and hydrogen levels were obtained in the control films made with H2OH2O than the films made with O3.O3. A reaction mechanism of the TEMAH+O3TEMAH+O3 ALD process is discussed. The results show that an O3O3 -based ALD HfO2HfO2 deposition is promising for microelectronic applications. © 2005 The Electrochemical Society. All rights reserved. More »»
2002 Journal Article A. R. Londergan, Ramanathan S., Vu, K., Rassiga, S., Hiznay, R., Winkler, J., Velasco, H., Matthysse, L., Seidel, T. E., Ang, C. H., and , “Process Optimization in Atomic Layer Deposition of High-K Oxides for Advanced gate Stack Engineering”, Rapid Thermal and Other Short-Time Technologies III, ECS, Pennington, pp. 163 - 176, 2002.
1999 Journal Article S. T. Oyama, C. Yu, C., and Ramanathan S., “Transition Metal Bimetallic Oxycarbides: Synthesis, Characterization, and Activity Studies”, Journal of Catalysis, vol. 184, pp. 535 - 549, 1999.[Abstract]

A new family of bimetallic oxycarbide compounds MI–MII–O–C (MI=Mo, W; MII=V, Nb, Cr, Fe, Co, Ni) has been synthesized by carburizing bimetallic oxide precursors using a temperature-programmed method. The oxide precursors are prepared by conventional solid-state reaction between two appropriate monometallic oxides. The synthesis involves passing a 20 mol% \{CH4\} in \{H2\} mixture over the oxide precursors while raising the temperature at a linear rate of 8.3×10−2 K s−1 (5 K/min) to a final temperature (Tmax) which is held for a period of time (thold). The synthesis, chemisorption properties, and reactivation of the materials indicate that the compounds can be divided into two groups of different reducibility (high and low). Their surface activity and surface area are evaluated based on \{CO\} chemisorption and \{N2\} physisorption measurements. It is found that the \{CO\} number density correlates with the reducibility of the compounds. The catalysts were evaluated for hydroprocessing in a three-phase trickle-bed reactor operated at 3.1 \{MPa\} and 643 K. The feed was a model liquid mixture containing 3000 ppm sulfur (dibenzothiophene), 2000 ppm nitrogen (quinoline), 500 ppm oxygen (benzofuran), 20 wt% aromatics (tetralin), and balance aliphatics (tetradecane). The bimetallic oxycarbides had moderate activity for \{HDN\} of quinoline, with Nb–Mo–O–C showing higher \{HDN\} than a commercial sulfided Ni–Mo/Al2O3 catalyst tested at the same conditions. X-ray diffraction of the spent catalysts indicated that the oxycarbides of the early transition metals were tolerant of sulfur, while those involving the late transition metals showed bulk sulfide phases. More »»
1998 Journal Article C. C. Yu, Ramanathan S., and Oyama, S. T., “New Catalysts for Hydroprocessing: Bimetallic Oxynitrides MI–MII–O–N (M”, Journal of Catalysis, vol. 173, pp. 1 - 9, 1998.[Abstract]

A new family of bimetallic oxynitride compounds, MI–MII–O–N (M More »»
1998 Journal Article B. Dhandapani, Ramanathan S., Yu, C. C., Frühberger, B., Chen, J. G., and Oyama, S. T., “Synthesis, Characterization, and Reactivity Studies of Supported Mo2C with Phosphorus Additive”, Journal of Catalysis, vol. 176, pp. 61 - 67, 1998.[Abstract]

The effect of phosphorus on Mo2C supported on γ-Al2O3and activated carbon was studied. The catalysts were characterized by \{CO\} chemisorption, \{BET\} surface area measurements, X-ray diffraction, X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure, and tested for their reactivity for hydroprocessing reactions, particularly hydrogenation, hydrodesulfurization (HDS) and hydrodenitrogenation (HDN), using model liquid compounds. The P-containing catalysts had higher reactivity for \{HDN\} than those without P. \{HDS\} was higher when the Mo2C was synthesized on γ-Al2O3previously treated with P than when the Mo component and P were added together on γ-Al2O3. Postreaction characterization indicates that the catalysts were tolerant of sulfur. More »»
1998 Journal Article Ramanathan S., Oyama, S. T., and C., C., “New Catalysts for Hydroprocessing: Bimetallic Oxynitrides MI-MII-O-N (MI, MII= Mo, W, V, Nb, Cr, Mn, and Co) Part II: Reactivity Studies”, Journal of Catalysis, pp. 10-16, 1998.
1997 Journal Article C. C. Yu, Ramanathan S., Dhandapani, B., Chen, J. G., and S. Oyama, T., “Bimetallic Nb−Mo Carbide Hydroprocessing Catalysts:  Synthesis, Characterization, and Activity Studies”, The Journal of Physical Chemistry B, vol. 101, pp. 512-518, 1997.[Abstract]

A series of Nb1.0MoxOC (x = 0.67−2.0) catalysts were prepared by a temperature-programmed reaction technique. The catalysts were synthesized from oxide precursors in a flow of 20% CH4/H2 reactant gas mixture, while the temperature was increased linearly at 5 K/min (8.3 × 10-2 K s-1). The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS), elemental analysis, CO chemisorption, surface area measurements, and temperature-programmed reduction. XRD patterns of the fresh catalysts indicated that Nb1.0Mo1.5OC and Nb1.0Mo1.75OC consisted of pure bimetallic carbide phases, while the other compositions showed impurity phases of NbO2 or Mo2C at high concentrations of Nb and Mo, respectively, in the starting oxide. The hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) activity of these materials was studied in a high-pressure reactor system. The reactions were carried out at 3.1 MPa and 643 K using model liquid compounds containing moderate concentrations of sulfur, nitrogen, oxygen, and aromatics. All the catalysts were found to be active for quinoline HDN, and the activity did not show much variation with changes in the ratio of the two metals (Mo/Nb). However, the HDS activity was found to be more sensitive to the composition (Mo/Nb) and Nb1.0Mo1.75OC showed the highest HDS activity among the catalysts tested. The bimetallic compounds showed enhancement in the activity and stability compared to the corresponding monometallic carbides. X-ray diffraction patterns of the spent catalysts did not show any sulfide, oxide, or metal peaks, indicating that the catalysts were stable and tolerant of sulfur. More »»
1995 Journal Article Ramanathan S. and Oyama, S. T., “New Catalysts for Hydroprocessing: Transition Metal Carbides and Nitrides”, The Journal of Physical Chemistry, vol. 99, pp. 16365-16372, 1995.
1994 Journal Article C. C. Yu, Ramanathan S., Sherif, F., and S. Oyama, T., “Structural, Surface, and Catalytic Properties of a New Bimetallic V-Mo Oxynitride Catalyst for Hydrodenitrogenation”, The Journal of Physical Chemistry, vol. 98, pp. 13038-13041, 1994.

Peer Reviewed International Journals (Under Review)

  1. A.V. Akhil, D. D Raj, M.K. Raj, S.R Bhat, V.Akshay, S.Bhomwik and S. Ramanathan., Effect of Low Pressure Plasma and Ultra Violet Radiation on Vaporized Solvent Bonding of Transparent Polymer, submitted to Journal of Polymer Engineering and Science IF 1.42.
  2. S. Sharma, A. Maalavan, A. Nivetha, K. Sivasubramanian, S. Sreekumar, S. Bhowmik, S. Ramanathan, R. Rane and S. Mukherjee, Electrical Conductive Coating on polymeric composites to prevent lightening strike damage on aircraft, submitted to Journal of Composites A IF 2.6.

Membership in Professional Bodies

  1. American Vacuum Society
  2. American Chemical Society
  3. Electrochemical Society

Student Guidance

Doctoral Students

  1. Development of Ulta High Temperature Resistance Polymeric Nanocomposites for Long Distance Space Applications”(Mr.P.Mohankumar)-Ongoing - Co-Supervisor
  2. “Development of Metal/Poly Ether Ether Ketone Hybrid Composite Laminates for Nuclear Waste Storage Containers” (Mr. Manu Remanan)-Ongoing-- Co-Supervisor
Faculty Details


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